responder

responder — noun

1. a person whose job is to provide help in dangerous or emergency situations, such

1.nounB2
Definition

a person whose job is to provide help in dangerous or emergency situations, such as a police officer, firefighter, or paramedic — for example, the personnel who arrive at the scene of a car accident, a fire, or a natural disaster.

Example

When the apartment building caught fire, over forty responders arrived within minutes.

quantifier + plural 'responders' for a team

Christopher works as a first responder for the Chicago fire department.

compound: first responder

Common collocations
  • first responder
  • emergency responder
  • trained responder
  • volunteer responder
  • responder unit
  • responder team
Synonyms
  • first responder

    more specific — refers to the first trained professionals arriving at the scene (police, paramedics, firefighters)

  • rescue worker

    broader — can include volunteers and search teams, not necessarily the first to arrive

  • emergency worker

    nearly synonymous but slightly more general; includes hospital emergency room staff who may not go to the scene

Grammar Patterns

first responder

emergency responder + verb (arrive / help / rescue)

responder + at / on + [location]

Usage Note

Often used in the compound noun 'first responder', which describes a person with special training who is among the first people to arrive at an accident or emergency. The plural 'responders' is very common when referring to organised response teams (police, fire, medical services working together).

Common Mistakes

The firefighter is a first responder to the scene.
The firefighter is a first responder at the scene.
'first responder' is a role title, not a verb phrase; use 'at' or 'on' for location, not 'to'.

2. a person who gives an answer, reply, or reaction to a question, message, or situ

2.nounB2
Definition

a person who gives an answer, reply, or reaction to a question, message, or situation — someone who responds verbally or in writing.

Example

I sent a message to the group chat, but only one responder replied so far.

Camila posted a question in the online forum, and three responders replied within five minutes.

scenario: forum posting with multiple responders in a reply context

Common collocations
  • quick responder
  • slow responder
  • first responder to a question
  • email responder
Synonyms
  • respondent

    more formal; preferred in legal, research, and official contexts

  • answerer

    very rare in modern English; use 'responder' or 'respondent' instead

  • replier

    informal and less common; 'responder' is the standard choice

Grammar Patterns

responder + to + [question / message / email]

adjective + responder (quick / slow / first)

Usage Note

Less formal than 'respondent'. This sense is common in everyday workplace communication (emails, meetings, chat groups). The pattern 'first responder to + [question/topic]' is particularly frequent in meeting contexts but is distinct from the compound 'first responder' in sense 1.

Common Mistakes

He is a responder fast.
He is a fast responder.
The adjective must come before the noun in English noun phrases.

3. a person who answers questions in a survey, questionnaire, or research study — s

3.nounB2
Definition

a person who answers questions in a survey, questionnaire, or research study — someone whose responses are collected and analysed by researchers.

Example

The survey had over two thousand responders, most of whom were university students.

quantifier + survey + responders

Each responder in the study answered a set of questions about their daily eating habits.

pattern: responder + in + [study]

Common collocations
  • survey responder
  • study responder
  • responder group
  • responder rate
  • number of responders
Synonyms
  • respondent

    the standard formal term in social science research and legal contexts

  • participant

    broader — includes people who take part in experiments, not just surveys

  • interviewee

    specific to face-to-face or telephone interview settings

Grammar Patterns

survey responder

responder + in + [study / survey / poll]

responder + to + [questionnaire]

Usage Note

In formal research writing, 'respondent' is more common than 'responder'. However, 'responder' appears frequently in spoken research contexts, data reports, and informal academic discussion. The preposition 'in' (not 'of') is used: 'responders in the study'.

Common Mistakes

There were 200 responders of the survey.
There were 200 responders in the survey.
Use 'in' (not 'of') when stating the number of participants in a study.

4. a patient whose medical condition improves as a result of a specific treatment,

4.nounC1
Definition

a patient whose medical condition improves as a result of a specific treatment, drug, or therapy — for example, a cancer patient whose tumour shrinks after chemotherapy, or a person whose blood pressure drops after taking medication.

Example

About sixty percent of patients were good responders to the new cancer drug.

pattern: good/poor responder + to + [treatment]

Doctors classified Henry as a responder because his symptoms improved after six weeks of treatment.

verb: classify + as + a responder

Common collocations
  • good responder
  • poor responder
  • responder to treatment
  • responder rate
  • responder analysis
Synonyms
  • respondent

    not used in this medical sense; 'respondent' is legal/research, not clinical

  • good responder

    specifies that the response was strong or complete

  • partial responder

    indicates that improvement was present but limited

Antonyms
  • non-responder

    a patient who does not improve with the given treatment

Grammar Patterns

responder + to + [treatment / drug / therapy]

good responder / poor responder

Usage Note

Primarily used in medical research and clinical contexts. The term is often paired with its opposite 'non-responder'. The preposition 'to' is required before the treatment: 'a responder to the vaccine'. In everyday hospital conversation, doctors may say 'he responded well' rather than 'he was a responder'.

Common Mistakes

She is a responder of the treatment.
She is a responder to the treatment.
Use 'to' (not 'of') when specifying the treatment a patient responded to.

Word family

Synonym discussion

Sense: noun/1

All four terms describe people who help in emergencies, but they differ in specificity. 'First responder' is the most precise: it refers to the first trained professionals (police, firefighters, paramedics) who arrive at the scene of an accident or crime — the term carries a note of official certification. 'Responder' alone is broader and includes anyone whose role is to respond to emergencies, whether or not they are the first to arrive. 'Rescue worker' focuses on the act of extracting people from danger (rescue from collapsed buildings, floods, or mountain accidents) and can include volunteers. 'Emergency worker' is the most general, encompassing all staff in the emergency services chain, including dispatchers and hospital staff who never visit the scene. 'Paramedic' is the narrowest: a specific medical professional trained to give emergency treatment on site. In news reports, 'responder' and 'first responder' are often used interchangeably, but in official contexts the distinction matters — for example, a paramedic is always a first responder, but a first responder is not necessarily a paramedic.

first responderrescue workeremergency workerparamedic

Common collocations

Nouns

Adverbs

Phrases

  • responder to a question
  • responder to treatment
  • first responder on the scene

Prepositions

Etymology

LatinFrenchEnglish

The word 'responder' is formed by adding the agent suffix '-er' (meaning 'a person who does something') to the verb 'respond'. 'Respond' itself comes from Latin 'respondēre', which means 'to answer back' — a combination of 're-' ('back') and 'spondēre' ('to promise, to pledge'). The noun entered English in the 16th century, originally meaning simply 'a person who answers'. The specific emergency-services sense emerged in the late 20th century with the professionalisation of disaster response, and the compound 'first responder' became widely used in the 1970s and 1980s in the United States.