The Collaborative International Dictionary of English v.0.48:
Wistful \Wist"ful\, a. [For wishful; perhaps influenced by
wistly, which is probably corrupted from OE. wisly certainly
(from Icel. viss certain, akin to E. wit). See Wish.]
1. Longing; wishful; desirous.
Lifting up one of my sashes, I cast many a wistful,
melancholy look towards the sea. --Swift.
2. Full of thought; eagerly attentive; meditative; musing;
That he who there at such an hour hath been,
Will wistful linger on that hallowed spot. --Byron.
[1913 Webster] -- Wist"ful*ly, adv. -- Wist"ful*ness,