The Collaborative International Dictionary of English v.0.48:
Infernally \In*fer"nal*ly\, adv. In an infernal manner; diabolically. "Infernally false." --Bp. Hacket. [1913 Webster]WordNet (r) 3.0 (2006):
infernally adv 1: extremely; "infernally clever"; "hellishly dangerous" [syn: infernally, hellishly]