thick as thieves

Adjective

Meaning

(as) thick as thieves (not comparable)

(idiomatic, simile, of friends or members of a group) Intimate, close-knit, tight.

Source: en.wiktionary.org

Synonyms

pally chummy buddy-buddy

Antonyms

formal distant casual

Close letter words and terms

thick as pea soup thick as pig shit thick as pigshit thick as two short planks thick blanket thick book