thick as thieves
Intimate, close-knit, tight.
Meaning adapted from Wiktionary, available under CC BY-SA 4.0.
“The two new coworkers are as thick as thieves.”
“The two neighbors are thick as thieves and share every secret.”
“Ever since they started working on the project together, those two have been as thick as thieves.”
“My cousins are thick as thieves and always whisper together in the corner during our large family holiday dinners.”
“After spending the whole summer at camp together, the boys returned home thick as thieves and refused to spend a day apart.”
“Despite their vastly different backgrounds, the two conspirators became as thick as thieves while planning their daring escape from the city.”
first recorded 19th c.
First attested in 1827 as the longer variant "thick as two thieves," the idiom derives from a specific sense of the word thick denoting a state of close, private intimacy. It implies a degree of friendship so concentrated that the parties involved might reasonably be suspected of conspiring in a shared criminal enterprise. The 1827 citation marks the transition of this particular use of thick from a description of proximity into a fixed social comparison.
- 01
blood is thicker than water
Family relations and loyalties are stronger than relationships with people who are not family members.
- 02
come thick and fast
To arrive rapidly in large groups.
- 03
lay it on thick
To exaggerate or overstate a feeling or emotion.
- 04
tea leaf
[Cockney slang]thief
- 05
thick and thin
Both good and bad times.
- 06
thick and threefold
In quick succession, or in great numbers.
- 07
thick end
Most; the greater part (of an amount of money).
- 08
thick of things
A central or major role in a situation; a position in which one is surrounded by or very involved in complex, changing events.
Last updated August 10, 2026