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thick as thieves

thick as thieves

7 7.4
Very close friends who share secrets and help each other
  • idiom
  • Informal
translation icon : íntimos
  • My best friend and I are thick as thieves; we share everything with each other.

So I mean, me and her, we're thick as thieves now.

Examples

  • St. Ed was right; they were thick as thieves.

    Fiction book (1993)
  • You know, you're obviously as thick as thieves in this precinct.

  • You guys are thick as thieves.

  • For seven years, me and your old man were as thick as thieves.

  • We were thick as thieves.

  • The two of you are as thick as thieves.

    Fiction book (1990)
  • "Listen," Henry said, "tonight we're thick as thieves."

    Fiction book (2000)
  • The three were thick as thieves.

    Fiction book (1999)
  • Well, they're certainly as thick as thieves.

  • That sheriff, the judge, the mayor, and the county commissioner, they're as thick as thieves.

    Fiction book (1995)

Synonyms

tight-knit
vsthick as thieves
16 3.6

People in a group who know each other well and help each other

focuses on close personal friendships often sharing secrets
thick
vsthick as thieves
  • UK
16 7.8

Being very friendly and close to someone

includes close friendship that involves sharing secrets or collaboration
hand in glove
vsthick as thieves
  • Informal
2 7.0

Working very closely in a secret or dishonest way

means friendly closeness involving shared secrets not only collusive work
closely knit
vsthick as thieves
1 3.7

A group of people who help and support each other

emphasizes personal closeness and secret collaboration rather than social bonds

Antonyms

61 4.9

Not friendly or warm, behaving in a quiet, cold way

40 6.7

No longer close or warm to someone you used to know well

How Close

inseparable
46 3.4
thick as thieves
  • Informal
7 7.4
close
1.3
friendly
773 1.0
acquainted
1 3.9

Surface Forms

thick as thieves positive

Morphology

thick + as + thief

The expression uses the familiar comparative pattern 'as ... as', so learners can tell it's a simile, but the attributive sense of 'thick' = 'very close' is non-literal and may be unknown to a B1 learner who only knows the basic senses. The reference to 'thieves' is figurative (implying collusion or secrecy) rather than literal, so the overall meaning is partly inferable from form and partly idiomatic, making it not fully predictable without exposure.

Etymology

Thick as thieves may come from the image of real thieves who must stay very close and trust each other to hide plans and secrets. That is why the phrase now means 'very close' and 'sharing secrets'.