Source : Webster's Revised Unabridged Dictionary (1913)

Intransitively \In*tran"si*tive*ly\, adv. (Gram.)
   Without an object following; in the manner of an intransitive
   verb.

Source : WordNet®

intransitively
     adv : in an intransitive manner; "you can use the verb `drink'
           intransitively, without a direct object" [ant: {transitively}]