The Collaborative International Dictionary of English v.0.48:
Plausive \Plau"sive\, a. [L. plaudere, plausum, to applaud.] 1. Applauding; manifesting praise. --Young. [1913 Webster] 2. Plausible, specious. [Obs.] --Shak. [1913 Webster]WordNet (r) 3.0 (2006):
plausive adj 1: expressing or manifesting praise or approval; "approbative criticism"; "an affirmative nod" [syn: approving, affirmative, approbative, approbatory, plausive]