wistful adj.

1610s, "closely attentive," perhaps from obsolete wistly "intently" (c. 1500), of uncertain origin. Perhaps formed on the model of wishful. Middle English wistful meant "bountiful, well-supplied," from Old English wist "provisions." The meaning of "longingly pensive, musing" is by 1714. Related: Wistfully; wistfulness.