as thick as thieves Definition

thick
adj thicker, thickest

1. Having a relatively large distance between opposite sides.
2. Having a specified distance between opposite sides.

Example: one inch thick
3. Having a large diameter.

Example: a thick rope
4. Said of a line or handwriting, etc: broad.
5. Said of liquids: containing a lot of solid matter.

Example: thick soup
Thesaurus: syrupy, coagulated, viscous, dense, turbid, clotted, gummy.
6. Having many single units placed very close together; dense.

Example: thick hair
Thesaurus: dense, condensed, compact, compressed, crowded, packed, close.
7. Difficult to see through.

Example: thick fog
8. Covered with or full of it.

Example: a cake thick with chocolate
Form: thick with something (usually)
9. Said of speech: not clear.

Thesaurus: inarticulate, muffled, garbled, indistinct.
10. Said of an accent: marked; pronounced.

Thesaurus: pronounced, conspicuous.
11. colloq
Said of a person: stupid; dull.
Thesaurus: stupid, obtuse, ignorant, dull, doltish.
12. colloq
Friendly or intimate.
Example: He is very thick with the new manager
Thesaurus: intimate, friendly, familiar, fraternal, cordial.
Form: thick with someone (usually)
13. colloq
Unfair
Example: That's a bit thick!

adverb

1. Thickly.

noun

1. The busiest, most active or most intense part.

Example: in the thick of the fighting
Form: the thick
2. The thickest part of anything.

Derivative: thickly
adverb

Idiom: as thick as thieves

Very friendly.

Idiom: thick and fast

Frequently and in large numbers.

Idiom: through thick and thin

Whatever happens; in spite of any difficulties.

Etymology: Anglo-Saxon thicce.