The cavity beneath the junction of the arm and shoulder. / Somewhere or something considered unpleasant or undesirable.

plural of armpit

(in combination) Having armpits of a specified kind.

(slang) A simulation of the sound of flatulence, made by creating a pocket of air between the armpit of a partially raised arm and the hand, and then swiftly closing this pocket by bringing the arm close to the torso.

plural of armpit fart