mid-13c., alteration (by influence of Scandinavian forms) of Old English wa la wa, literally "woe, lo, woe!" from wa "woe" (see woe).
Entries linking to wellaway
woe n.
late 12c., from the interjection, Old English wa!, a common exclamation of lament in many languages (compare Latin væ, Greek oa, German weh, Lettish wai, Old Irish fe, Welsh gwae, Armenian vay).