(idiomatic) A joke, especially one which strikes the listener or reader as particularly humorous.

Reaching up to the knees. / Submerged to the knees. / (figuratively, by extension) Deeply involved in something, or preoccupied with something.

Alternative spelling of knock knee

(slang) A casual outdoor sexual encounter (commonly with a prostitute), usually in an alleyway or against a wall, with the man standing and the woman's knees raised.

The medical condition genu valgum

Alternative spelling of kneecapping

(baseball, slang) A curveball (or occasionally a knuckleball) that fools the hitter, causing his or her knees to buckle (i.e. bend).

plural of knee baby

Breeches reaching down to or just below the knee.

plural of knee pit