in deep

Idioms  

1. 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 .

2. 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 .

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Example Sentences

See Examples For:

in deep

The findings raise the possibility that changes in deep sleep activity could eventually help researchers better understand or identify early memory problems.

From Science Daily ● Nov. 5, 2026

"Evidence of systematic violence is extremely rare in deep prehistory. The vast majority comes from periods of settled farming communities thousands of years after hunter-gather societies like our Neanderthals."

From Science Daily ● Oct. 31, 2026

Another furious attack towards the end of the round left Wardley in deep trouble.

From BBC ● Oct. 17, 2026

Japan undoubtedly has an edge in deep technology and entertainment content, Tomita said.

From The Wall Street Journal ● Oct. 1, 2026

Max leaned his head back against the leather seat and took in deep, relieved gulps of air.

From "The School for Whatnots" by Margaret Peterson Haddix

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