Source : Webster's Revised Unabridged Dictionary (1913)

Longingly \Long"ing*ly\, adv.
   With longing. --Dryden.

Source : WordNet®

longingly
     adv : in a yearning manner; "he spent the rest of the act gazing
           longingly over my right shoulder at the illuminated
           word `Exit'" [syn: {with longing}, {yearningly}]