allergic

allergic — adjective

1. If a person or animal is allergic to a food, plant, animal, or other substance,

1.adjectiveA2
Definition

If a person or animal is allergic to a food, plant, animal, or other substance, their body reacts badly when they touch, eat, or breathe it in, often causing a rash, sneezing, or trouble breathing.

Example

Mia is allergic to peanuts, so her mother always checks the menu carefully.

be allergic to + food noun

Many children are allergic to cat hair and start sneezing within minutes.

plural subject + 'allergic to'

Common collocations
  • allergic to peanuts
  • allergic to dust
  • allergic to penicillin
  • highly allergic
  • severely allergic
Synonyms
  • hypersensitive

    more medical and formal; often used in clinical writing

  • intolerant

    wider — covers food intolerance that is not strictly an immune reaction

Grammar Patterns

be allergic to + noun

Usage Note

Almost always used with the preposition 'to' followed by the trigger (food, animal, drug, plant). Subject is usually a person or animal — distinguish from sense 2, where the subject is the reaction or condition itself.

Common Mistakes

I am allergic with milk.
I am allergic to milk.
the fixed preposition is 'to', not 'with' or 'from'.
She has allergic to dust.
She is allergic to dust.
'allergic' is an adjective, so use 'be', not 'have'.

2. Used before a noun to describe a rash, swelling, cough, or other physical proble

2.adjectiveB1
Definition

Used before a noun to describe a rash, swelling, cough, or other physical problem that the body produces because of an allergy.

Example

The bee sting gave Daniel a severe allergic reaction within ten minutes.

collocation: severe allergic reaction

Doctors treated the boy for an allergic rash on his arms and neck.

allergic + body symptom noun

Common collocations
  • allergic reaction
  • allergic rash
  • allergic asthma
  • allergic shock
  • allergic response
Synonyms
  • anaphylactic

    much stronger and life-threatening; only for the most severe reactions

Grammar Patterns

allergic + medical noun

Usage Note

Only sense that sits directly before a noun (attributive only). The noun describes the symptom or condition (reaction, rash, asthma, shock), not the person. Distinguish from sense 1, where the person is allergic and the structure uses 'be allergic to'.

Common Mistakes

The cream made my skin allergic.
The cream caused an allergic reaction on my skin.
the symptom is allergic, not the body part itself.

3. Strongly disliking someone or something, or trying very hard to avoid an activit

3.adjectiveB2
Definition

Strongly disliking someone or something, or trying very hard to avoid an activity, in a joking or exaggerated way.

Example

My brother is allergic to housework and disappears whenever I bring out the vacuum.

informal humour: allergic to + activity noun

Teenagers seem to be allergic to getting up before noon on weekends.

be allergic to + -ing form

Common collocations
  • allergic to hard work
  • allergic to housework
  • allergic to commitment
  • allergic to change
Synonyms
  • averse

    more formal; often appears with 'risk' in business writing

  • opposed

    stronger and more public; used about views and policies, not personal habits

Antonyms
  • fond of

    opposite informal feeling: liking something rather than avoiding it

Grammar Patterns

be allergic to + noun / -ing

Usage Note

Informal and usually humorous — never used in serious medical or formal writing. Frequently followed by an -ing verb naming the disliked activity. Distinguish from sense 1 by context: a real medical trigger (peanuts, dust) signals sense 1, while an activity or abstract noun (housework, hard work) signals sense 3.

Common Mistakes

He is allergic about hard work.
He is allergic to hard work.
keep the preposition 'to', the same as sense 1.

Word family

  • allergy
    nounA2
  • allergen
    nounC1
  • allergist
    nounC1
  • hypoallergenic
    adjectiveC1

Synonym discussion

Sense: adjective/1

All four words describe a body that reacts badly to something, but the reasons and registers differ. 'Allergic' is the common everyday word and almost always pairs with 'to' plus a specific trigger such as peanuts, pollen, or a drug. 'Hypersensitive' is more clinical and appears in medical writing or formal reports; it can also describe emotional over-reaction in non-medical contexts. 'Intolerant' is broader: a person can be lactose intolerant without their immune system being involved at all, so doctors prefer it for digestive problems. 'Sensitive' is the mildest of the four — sensitive skin may sting from soap without producing a true allergic reaction. Compare: 'Mia is allergic to milk' (immune response, can be serious) vs 'Mia is lactose intolerant' (digestive only) vs 'Mia has sensitive skin' (mild reaction to creams).

allergic ↗hypersensitiveintolerantsensitive ↗

Common collocations

Nouns

  • allergic reaction
  • allergic rash
  • allergic asthma
  • allergic shock
  • allergic response
  • allergic patient

Adverbs

  • highly allergic
  • severely allergic
  • mildly allergic
  • violently allergic

Phrases

  • be allergic to
  • develop an allergic reaction
  • trigger an allergic response

Prepositions

  • allergic to

Etymology

GreekGermanEnglish

Built from the noun 'allergy', which itself was put together in 1906 by an Austrian doctor from two Greek pieces — 'allos' meaning 'other' and 'ergon' meaning 'work' or 'reaction'. The idea was that the body was doing some 'other kind of work' against a normally harmless substance. The adjective 'allergic' followed soon after in English, and by the mid-1900s people had also started using it jokingly to mean 'strongly disliking' something.