Английский Этимологический словарь - strut (v.)

- "walk in a vain, important manner," O.E. strutian "to stand out stiffly," from P.Gmc. *strut-. Originally of the air or the attitude; modern sense, focused on the walk, first recorded 1518. Cognate with O.E. рrutung "anger, arrogance" (see throat). To strut (one's) stuff is black slang, first recorded 1926, from strut as the name of a dance popular from c.1900.