From Old French a las (French hélas), from a (“ah”) + las, from Latin lassus (“weary”). Compare Dutch helaas.
From Latin laxō. Compare Daco-Romanian lăsa, las.
Blend of a + las. From Spanish a las.
From Proto-Finnic *alas, from Proto-Uralic *ëla. Cognates include Estonian all and Hungarian alatt (the lative singular of ala-).
From Hungarian halász (“fisherman”).