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

"We are in deep pain, and we ask for time and privacy as we come to terms with our loss."

From BBC ● Aug. 6, 2026

"We are living in deep fear and cannot even eat the food we are given," said Habtom.

From BBC ● Jul. 31, 2026

“I’ve come to admire artists who are willing to go in deep inside their most personal thoughts for the sake of helping the listener understand their own lives,” he said.

From Los Angeles Times ● Jul. 3, 2026

Based on that relationship, greater activity in Purkinje cells would be expected to correspond with lower activity in deep nuclei cells, while reduced Purkinje activity would be expected to have the opposite effect.

From Science Daily ● Jul. 1, 2026

The room is outfitted in deep reds and oranges like a phoenix's feathers.

From "The Belles" by Dhonielle Clayton