The Collaborative International Dictionary of English v.0.48:
Insipidly \In*sip"id*ly\, adv. In an insipid manner; without taste, life, or spirit; flatly. --Locke. Sharp. [1913 Webster]WordNet (r) 3.0 (2006):
insipidly adv 1: in an insipid manner; "insipidly expressed thoughts"