underarm >> ˈʌndərɑːm
Definition: [noun] a person's armpit.
Example: she shaved her legs and underarms
Definition: [adjective] (of a throw or stroke in sport) made with the arm or hand below shoulder level.
Example: a good-length underarm serve
Definition: [adverb] (with reference to a throw or stroke in sport) with the arm or hand below shoulder level.
Example: throwing underarm