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 .

---

Example Sentences

"Relations remain in deep freeze," former Pakistani diplomat, Husain Haqqani, now a senior fellow at Anwar Gargash Diplomatic Academy and Hudson Institute, told the BBC.

From BBC • May 7, 2026

Catsimatidis made millions from buying New York real estate on the cheap in the 1970s when the city was in deep economic trouble.

From Los Angeles Times • Apr. 22, 2026

They have won pretty much everywhere with a wide range of candidates—in special elections and regular elections in deep red territory and in more contested geographies, running candidates of the far left and the center-left.

From The Wall Street Journal • Apr. 6, 2026

"We continue to learn all about our spacecraft as we operate it in deep space with crew for the first time," Hawkins said.

From Barron's • Apr. 3, 2026

Hesitating under the straggling fringe of palm fronds, he peered into the shop’s interior, which seemed in deep gloom after the blaze of sun in the road.

From "The Golden Goblet" by Eloise Jarvis McGraw