Source : Webster's Revised Unabridged Dictionary (1913)

Felicitous \Fe*lic"i*tous\, a.
   Characterized by felicity; happy; prosperous; delightful;
   skilful; successful; happily applied or expressed;
   appropriate.

         Felicitous words and images.             --M. Arnold.
   -- {Fe*lic"i*tous*ly}, adv. -- {Fe*lic"i*tous*ness}, n.

Source : WordNet®

felicitously
     adv : in a felicitous manner; "a not felicitously chosen word"
           [ant: {infelicitously}]