in deep

in deep

1. Fig. deeply involved (with someone or something). •

Mary and Sam are in deep.

•

Wilbur got in deep with the mob.

2. Fig. deeply in debt. (Often with

with

or

to

.) •

Willie is in deep with his bookie.

•

I'm in deep to the department store.

* * *

{adj. phr.} Seriously mixed up in something, especially trouble. * /George began borrowing small sums of money to bet on horses, and before he knew it he was in deep./ Compare: DEEP WATER, UP TO THE CHIN IN.