knee-deep • adj. immersed up to the knees: we were knee-deep in snow. ∎ having more than one needs or wants of something: we shall soon be knee-deep in conflicting legal views. ∎ so deep as to reach the knees: the water was knee-deep on Main Street.• adv. so as to be immersed up to the knees: I plodded knee-deep through the mud.