alas: [13] In origin alas was an exclamation of weariness rather than grief. Latin lassus ‘weary’ (related to let ‘a(chǎn)llow’ and source of lassitude) passed into Old French as las which, with the addition of the exclamation a ‘a(chǎn)h’, became alas. => lassitude, let
alas
mid-13c., from Old French ha, las (later French hélas), from ha "ah" + las "unfortunate," originally "tired, weary," from Latin lassus "weary" (see late). At first an expression of weariness rather than woe.