From Longman Dictionary of Contemporary Englishflusterflus‧ter1 /ˈflʌstə $ -ər/ verb [transitive] NERVOUSto make someone nervous and confused by making them hurry or interrupting them Don’t fluster me, or I’ll never be ready on time.→ See Verb table
Examples from the Corpus
fluster• The zone blitz can fluster an offense because it looks nothing like a conventional blitz.• But enough influential parishioners were angry to fluster the Parish Council and jeopardize the existence of the groups.flusterfluster2 noun British English → in a flusterExamples from the Corpus
fluster• She watched him seeing it all, feeling it all, assimilating his surroundings with no fidget or fluster.• But the fluster and the harassment were largely wasted, because Josie didn't return at all. 