出典:Wiktionary
出典:『Wiktionary』 (2026/01/01 18:55 UTC 版)
From under- + arm. The armpit sense is not old, historically speaking (1920s), and it is believed to have arisen as a euphemism in advertising.
underarm (not comparable)
underarm (third-person singular simple present underarms, present participle underarming, simple past and past participle underarmed)