having relatively great extent from one surface or side to the opposite; not thin

a thick slice.

measured, as specified, between opposite surfaces, from top to bottom, or in a direction perpendicular to that of the length and breadth; (of a solid having three general dimensions) measured across its smallest dimension

a board one inch thick.

composed of or containing objects, particles, etc., close together; dense

a thick fog; a thick forest.

filled, covered, or abounding (usually fol. by with )

tables thick with dust.

husky or hoarse; not distinctly articulated

The patient's speech is still quite thick.

markedly so (as specified)

a thick German accent.

deep or profound

thick darkness.

(of a liquid) heavy or viscous

a thick syrup.

Informal . close in friendship; intimate.

mentally slow; stupid; dull.

disagreeably excessive or exaggerated

They thought it a bit thick when he called himself a genius.

in a thick manner.

close together; closely packed

The roses grew thick along the path.

in a manner to produce something thick

Slice the cheese thick.

the thickest, densest, or most crowded part

in the thick of the fight.

lay it on thick

Informal . to praise excessively; flatter

He's laying it on thick because he wants you to do him a favor.

through thick and thin

under favorable and unfavorable conditions; steadfastly

We have been friends for 20 years, through thick and thin.