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

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in deep

What’s left is in deep water: expensive, technically perilous and less likely to strike oil.

From The Wall Street Journal ● Sep. 12, 2026

Fiel, vice president of brand and creative at the AI-native startup Newton, loves reinventions of utilitarian clothing, favoring functional pieces in deep greens and blacks.

From Los Angeles Times ● Sep. 11, 2026

“If you’re Loomered, you’re in deep trouble. That’s the end of your career, in a sense.”

From Salon ● Sep. 3, 2026

Their results indicate that changes in Agulhas Leakage do not always produce the expected response in deep water formation.

From Science Daily ● Aug. 6, 2026

Sometimes I saw her sit on the side of the bed for a while before getting up, drawing in deep breaths through thin, pursed lips.

From "The Poisonwood Bible" by Barbara Kingsolver