Meaning

noun a disposition that is confused or nervous and upset

verb be flustered; behave in a confused manner

verb cause to be nervous or upset

originThe verb is probably from Middle English *flostren (implied in flostring, flostrynge (“agitation; blustering”)) from a Scandinavian (North Germanic) language; compare Icelandic flaustra (“to bustle”), flaustr (“a bustle; a hurry”). Compare Old English flustrian (“to weave, plait, braid”). The noun is derived from the verb.

Etymology from Wiktionary, CC BY-SA 3.0