undertake

undertake — verb

1. to start working on a task, project, or responsibility, especially one that is l

1.verbtransitiveB2
Definition

to start working on a task, project, or responsibility, especially one that is large or challenging.

Example

The research team undertook a detailed survey of local river water quality last spring.

collocation: undertake a survey / a study / a project

Before undertaking any major home renovation, compare prices from at least three builders.

Common collocations
  • undertake a project
  • undertake a study
  • undertake a task
  • undertake research
  • undertake a review
  • undertake a journey
Synonyms
  • take on

    less formal; emphasises accepting a responsibility, often one offered by someone else

  • carry out

    focuses on the execution or completion rather than the start

  • embark on

    more literary; highlights the beginning of a long process or journey

Antonyms
  • abandon

    to stop doing something after starting it

  • avoid

    to stay away from a responsibility or task

Grammar Patterns

undertake + noun phrase (task / project / study / job)

Usage Note

Frequently used with nouns that describe work, research, or responsibilities (a project, a study, a task, a review). The object is typically something that requires effort over time.

Common Mistakes

He took over the project' (when meaning he started it).
He undertook the project
'take over' means you assume control from someone else; 'undertake' means you start or assume responsibility yourself.

2. to formally agree or promise to do something, often creating a sense of obligati

2.verbtransitiveB2
Definition

to formally agree or promise to do something, often creating a sense of obligation or commitment.

Example

The landlord undertook to repair the broken heating system within a week.

undertake + to-infinitive for a formal promise

Both governments have undertaken to cut carbon emissions by forty percent before 2035.

passive perfect: have undertaken to [verb]

Common collocations
  • undertake to pay
  • undertake to provide
  • undertake to complete
  • undertake to ensure
Synonyms
  • promise

    less formal; used in everyday situations

  • pledge

    stronger emotional or moral commitment; common in political contexts

  • commit to

    emphasises dedication and follow-through; takes a gerund or noun

Antonyms

Grammar Patterns

undertake + to-infinitive

Usage Note

Almost always followed by a to-infinitive clause ('undertook to do something'). Cannot take a that-clause (*'I undertook that I would go'). More formal than 'promise' or 'agree' — common in legal, business, and official contexts.

Common Mistakes

She undertook that she would finish by Friday.
She undertook to finish by Friday.
'undertake' takes a to-infinitive, not a that-clause.
I undertake I will help.
I undertake to help.
same rule.

3. to drive past a slower vehicle on its left side when both are travelling the sam

3.verbtransitiveB1
Definition

to drive past a slower vehicle on its left side when both are travelling the same way, as is done on British roads.

Example

On British motorways you may only undertake in slow-moving or queuing traffic.

British traffic rule context

Niran was fined for undertaking a lorry on the hard shoulder of the motorway.

Common collocations
  • undertake a lorry
  • undertake a car
  • undertake on the left
  • undertake in slow traffic
Synonyms
  • pass

    neutral, everyday term for going past another vehicle

  • overtake

    antonym in British driving context; means pass on the right

Antonyms
  • overtake

    in British English, passing on the right (the normal, legal manoeuvre)

Grammar Patterns

undertake + noun phrase (a car / a lorry / a bus)

Usage Note

The opposite of 'overtake'. In British driving, 'overtake' means pass on the right (the normal, legal way); 'undertake' means pass on the left, which is usually illegal except in slow-moving or queued traffic. This sense is rarely used outside the UK and Ireland.

Common Mistakes

He undertook the car on the right.
He undertook the car on the left.
'undertake' specifically means passing on the left side in British English.

Word family

Synonym discussion

Sense: verb/1

Undertake, take on, carry out, and embark on all relate to dealing with a task, but they highlight different stages. Undertake suggests starting a significant or challenging task with a sense of responsibility — you undertake a project knowing it will demand effort. Take on is similar but emphasises accepting something that was offered or assigned, such as taking on extra duties. Carry out focuses on execution and completion rather than the start — you carry out a plan that has already been decided. Embark on has a more literary feel and stresses the beginning of a process that resembles a journey, like embarking on a new career. For example: The city council undertook a major road-widening project (they took responsibility for the whole thing). The same team carried out the construction (they did the work). They took on the project after the previous contractor withdrew (they accepted it). They embarked on the second phase in 2025 (they started a new stage.)

take on ↗carry out ↗embark on ↗

Common collocations

Nouns

Adverbs

Phrases

  • undertake to do something
  • undertake a task
  • undertake a project

Prepositions

  • to (with infinitive)

Etymology

Old EnglishMiddle EnglishEnglish

Undertake comes from the prefix under- (from Old English 'under') and the verb take (from Old English 'tacan', meaning 'to seize or grasp'). The original sense was 'to take under one's control', which developed into 'to take on a responsibility' by the 13th century. The meaning 'to promise' emerged in the 14th century as a natural extension of taking on an obligation. The driving sense appeared much later in British English in the 20th century.