UNDERGARMENT Meaning of UNDERGARMENT in English ˈ ̷ ̷ ̷ ̷ˌ ̷ ̷ ̷ ̷ nounEtymology: under (III) + garment : a garment to be worn under another Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012