Synonym of knuckle under

(literally) to tap one's knuckles on an object such as a desk or wall to attract attention or as a signal of commmunication. / (somewhat dated, idiomatic) to give someone a punishment.

A compact crane whose boom articulates near the middle.

plural of knuckleboom

(slang, vulgar) Semen or ejaculate resulting from masturbation.

(informal) A credit card imprinter.

plural of knuckle-tat

Alternative spelling of moose knuckle

plural of moose-knuckle