'Infectiously' definitions:

Definition of 'infectiously'

From: WordNet
adverb
In a contagious manner; "she was contagiously bubbly" [syn: contagiously, infectiously]

Definition of 'Infectiously'

From: GCIDE
  • Infectiously \In*fec"tious*ly\, adv. In an infectious manner. --Shak. [1913 Webster]