adjective, thick·er, thick·est.

adverb, thick·er, thick·est.


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.

Origin of thick

before 900; (adj. and adv.) Middle English thikke, Old English thicce; cognate with Dutch dik, German dick; akin to Old Norse thykkr (noun) Middle English, derivative of the adj.
Related formsthick·ish, adjectivethick·ly, adverbo·ver·thick, adjectiveo·ver·thick·ly, adverbo·ver·thick·ness, nounsu·per·thick, adjectiveun·thick, adjectiveun·thick·ly, adverbun·thick·ness, noun

Synonyms for thick Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for through thick and thin



of relatively great extent from one surface to the other; fat, broad, or deepa thick slice of bread
  1. (postpositive)of specific fatnessten centimetres thick
  2. (in combination)a six-inch-thick wall
having a relatively dense consistency; not transparentthick soup
abundantly covered or filleda piano thick with dust
impenetrable; densea thick fog
stupid, slow, or insensitivea thick person
throaty or badly articulateda voice thick with emotion
(of accents, etc) pronounced
informal very friendly (esp in the phrase thick as thieves)
a bit thick British unfair or excessive
a thick ear informal a blow on the ear delivered as punishment, in anger, etc


in order to produce something thickto slice bread thick
profusely; in quick succession (esp in the phrase thick and fast)
lay it on thick informal
  1. to exaggerate a story, statement, etc
  2. to flatter excessively


a thick piece or part
the thick the busiest or most intense part
through thick and thin in good times and bad
Derived Formsthickish, adjectivethickly, adverb

Word Origin for thick

Old English thicce; related to Old Saxon, Old High German thikki, Old Norse thykkr
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for through thick and thin



Old English þicce "not thin, dense," from Proto-Germanic *theku-, *thekwia- (cf. Old Saxon thikki, Old High German dicchi, German dick, Old Norse þykkr, Old Frisian thikke), from PIE *tegu- "thick" (cf. Gaelic tiugh).

Secondary Old English sense of "close together" is preserved in thickset and proverbial phrase thick as thieves (1833). Meaning "stupid" is first recorded 1590s. Phrase thick and thin is in Chaucer (late 14c.); thick-skinned is attested from 1540s; in figurative sense from c.1600. To be in the thick of some action, etc., "to be at the most intense moment" is from 1680s, from a Middle English noun sense.

Online Etymology Dictionary, © 2010 Douglas Harper

through thick and thin in Medicine




Relatively great in extent from one surface to the opposite, usually in the smallest solid dimension; not thin.
Measuring a specified number of units in this dimension.
Heavy in form, build, or stature; thickset.
Having component parts in a close, crowded state or arrangement; dense.
Having or suggesting a heavy or viscous consistency.
Having a great number; abounding.
Impenetrable by the eyes.
Not easy to hear or understand; indistinctly articulated.
Noticeably affecting sound; conspicuous.
Producing indistinctly articulated sounds.


In a close, compact state or arrangement; densely.
In a thick manner; deeply or heavily.


The most active or intense part.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

through thick and thin in Culture

through thick and thin

To stay with someone or something “through thick and thin” is to persevere through good times as well as bad: “She stood beside her friend through thick and thin.”

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with through thick and thin

through thick and thin

Despite all obstacles or adversities, as in She promised to stand by him through thick and thin. This term alludes to penetrating a forest with both thick and sparse undergrowth. Today it is nearly always used with the idea of supporting something or someone in all circumstances, as in the example. [Late 1300s]


In addition to the idioms beginning with thick

  • thick and fast
  • thick and thin
  • thick as thieves
  • thick skin

also see:

  • blood is thicker than water
  • lay it on thick
  • plot thickens
  • through thick and thin
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.