A shy, childlike smile is an example of a winsome smile.
Origin of winsomeMiddle English winsum from Old English wynsum, pleasant, delightful from wynn, delight, joy (for Indo-European base see win) + -sum, -some
Origin of winsomeMiddle English winsum from Old English wynsum from wynn joy ; see wen-1 in Indo-European roots. -sum characterized by ; see -some 1.
(comparative more winsome, superlative most winsome)
From Middle English, from Old English wynsum (“winsome, pleasant, joyful, merry"), from Proto-Germanic *wunisamaz (“joyful"), from *wunjÅ (“joy, delight, desire"), from Proto-Indo-European *wun-, *wenÇ- (“to wish, love"), equivalent to winne +"Ž -some. Cognate with Scots winsome, wunsome (“charming, comely, pleasing"), Middle High German wunnesam (“winsome, joyful, delightful"), Old English wynn (“joy, rapture, pleasure, delight"), German Wonne (“bliss, delight, joy"). More at winne, winly.