'irrationally' definitions:

Definition of 'irrationally'

From: WordNet
adverb
In an irrational manner; "they acted irrationally" [ant: rationally]

Definition of 'irrationally'

From: GCIDE
  • irrationally \ir*ra"tion*al*ly\, adv. In an irrational manner. --Boyle. [1913 Webster]