YESSIR Meaning of YESSIR in English [ 'jɛsə , jɛs'sə: ]■ exclamation informal expressing assent, especially to a superior. ↘ N. Amer. expressing emphatic affirmation.Originearly 20th cent.: alt. of yes sir . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004