The Collaborative International Dictionary of English v.0.48:
Fluster \Flus"ter\, v. t. [imp. & p. p. Flustered; p. pr. & vb. n. Flustering.] [Cf. Icel. flaustra to be flustered, flaustr a fluster.] To make hot and rosy, as with drinking; to heat; hence, to throw into agitation and confusion; to confuse; to muddle. [1913 Webster] His habit or flustering himself daily with claret. --Macaulay. [1913 Webster]