[ deep ]
/ dip /

adjective, deep·er, deep·est.


adverb, deep·er, deep·est.

Idioms for deep

Origin of deep

First recorded before 900; Middle English dep, Old English dēop; akin to Gothic diups, Old Norse djupr, Dutch diep, Old High German tiof; akin to dip1, dive


1, 10, 15–17, 23 shallow.

OTHER WORDS FROM deep Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for in deep

/ (diːp) /




Derived forms of deep

deeply, adverbdeepness, noun

Word Origin for deep

Old English dēop; related to Old High German tiof deep, Old Norse djupr
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

Idioms and Phrases with in deep (1 of 2)

in deep


Seriously involved; far advanced. For example, He was in deep with the other merchants and couldn't strike out on his own, or She used her credit cards for everything, and before long she was in deep.


in deep water. Also, in over one's head. In trouble, with more difficulties than one can manage, as in The business was in deep water after the president resigned, or I'm afraid Bill got in over his head. These metaphoric expressions transfer the difficulties of being submerged to other problems. The first appears in Miles Coverdale's 1535 translation of the Book of Psalms (68:13): “I am come into deep waters.” The second, which also can signify being involved with more than one can understand, dates from the 1600s. Also see over one's head.

Idioms and Phrases with in deep (2 of 2)


In addition to the idioms beginning with deep

  • deep down
  • deep end
  • deep pocket
  • deep six
  • deep water

also see:

  • beauty is only skin deep
  • between a rock and a hard place (devil and deep blue sea)
  • go off the deep end
  • in deep
  • still waters run deep
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.