More about wistful
Wistful “pensive in a melancholy way” is likely a compound of the adjective whist (also wist) “quiet, silent, attentive” and the suffix -ful, perhaps because of the influence of the adjective wishful. As an interjection, whist is used to mean “hush! silence! be still!” Whist is likely of imitative origin and belongs to a class of similar-sounding interjections, along with hist, hush, and sh, that are used to demand silence. The sibilant sounds s and sh appear to be universal sounds indicating silence that appear in disparate languages, from Latin st to Finnish hys and Swahili usu. These widespread, common sounds are not the result of baby talk, as with the recent Word of the Day selection babushka; rather, they are onomatopoeic. Alternatively, wistful could simply be an alteration of the adverb wistly “with close intention.” Wistful was first recorded circa 1610.