thorough

thorough — adjective

1. done with very close attention to every part or step, making sure nothing is lef

1.adjectiveB2
Definition

done with very close attention to every part or step, making sure nothing is left out or forgotten.

Example

The head teacher gave the school's safety records a thorough check before the inspection.

collocation: thorough check / thorough inspection

Nikhil interviewed every stallholder for his thorough report on the market's history.

Common collocations
  • thorough check
  • thorough investigation
  • thorough cleaning
  • thorough search
  • thorough review
  • thorough research
  • thorough understanding
  • thorough knowledge
  • thorough examination
Synonyms
  • meticulous

    even greater attention to tiny details, often with a suggestion of fussiness

  • painstaking

    emphasises the effort and care put into the work

  • exhaustive

    implies nothing has been left out; often used for lists, research, or searches

  • systematic

    highlights an organised, step-by-step method rather than just carefulness

Antonyms

Grammar Patterns

be thorough (in/with something)

a thorough + noun

Usage Note

Frequently paired with nouns that describe work, study, or investigation — a thorough search, a thorough review, thorough research. In predicative position (after 'be'), it often takes 'in' or 'with': 'You should be more thorough in your preparation.'

Common Mistakes

The doctor did a through examination of the patient.
The doctor did a thorough examination of the patient.
'thorough' means careful and complete; 'through' means going from one side to the other.

2. used before an abstract noun to emphasise that something is total or extreme in

2.adjectiveB2
Definition

used before an abstract noun to emphasise that something is total or extreme in degree, especially when it is negative or undesirable — for example, a thorough mess, a thorough nuisance, or a thorough disgrace.

Example

The project became a thorough mess after the team lost its main data files.

intensifier: a thorough mess (negative noun)

After losing his wallet and missing the last train, Amir called the evening a thorough disaster.

Common collocations
  • thorough mess
  • thorough nuisance
  • thorough disgrace
  • thorough pleasure
  • thorough success
  • thorough waste
Synonyms
  • complete

    less formal and more common; works in the same positions

  • utter

    stronger negative connotation; used with disasters, nonsense, rubbish

  • absolute

    very similar to 'complete'; common with positive nouns too ('absolute delight')

  • total

    neutral, widely used with both positive and negative nouns

Antonyms
  • partial

    only part of something, not the whole degree

Grammar Patterns

a thorough + noun (abstract)

Usage Note

This sense is almost always attributive (before a noun) and cannot be used predicatively: you can say 'a thorough disgrace' but NOT ✗ 'the disgrace was thorough' with this meaning. The nouns it modifies are usually abstract (mess, nuisance, pleasure, success, disgrace, waste). When used with a positive noun (pleasure, success), it carries a slightly old-fashioned or emphatic tone.

Common Mistakes

The mess was thorough.
It was a thorough mess.
In this intensifier sense, 'thorough' must come before the noun, not after a linking verb.

thorough — adverb

thorough — preposition

Word family

  • thoroughly
    adverbB2
  • thoroughness
    nounC1
  • thoroughgoing
    adjectiveC2

Synonym discussion

Sense: adjective/1

All five words describe careful attention, but they differ in emphasis. Thorough is the broadest term — it means nothing is missed, and it fits everyday situations ('a thorough cleaning', 'a thorough report'). Meticulous draws attention to tiny details, sometimes to the point of fussiness ('a meticulous arrangement of the bookshelf'). Painstaking highlights the effort and time spent ('years of painstaking research'). Exhaustive suggests that every possible item has been covered, often used for lists or searches ('an exhaustive list of references'). Systematic emphasises method rather than intensity ('a systematic review of the evidence'). In daily conversation, thorough is the most natural choice; the others carry stronger or more specialised tones.

thorough ↗meticulous ↗painstaking ↗exhaustive ↗systematic ↗

Common collocations

Nouns

  • thoroughness

Adverbs

Phrases

Etymology

Old EnglishMiddle EnglishModern English

The word 'thorough' began as a spelling variant of 'through' in Middle English (1200s–1400s), when English spelling was not yet fixed. Both words go back to Old English 'þurh' (through). The adjective meaning 'careful and complete' grew out of the idea of going all the way through something — if you go through a task from start to finish without stopping, you have done a thorough job. By the 1500s, 'thorough' had split away from 'through' and become a distinct adjective, while the older uses as adverb and preposition gradually fell out of use.