An Etymological Dictionary of the German Language/selig
selig, adj., ‘happy, blessed, deceased, late,’ from MidHG. sœlec, OHG. sâlig, adj., ‘happy, blessed, blissful, salutary’; lengthened by the suffix -îg from an older *sâl, which was preserved in MidHG. sûllîche, ‘in a lucky manner’; comp. Goth. sêls, ‘good, suitable,’ AS. sœ̂lig, ‘good, happy,’ OHG. sâlida, MidHG. sœlde, f., ‘happiness, welfare.’ Goth. sêls is usually compared with Gr. ὅλος (Ion. οὖλος), ‘whole,’ from solvos, οὖλε, as a greeting, Sans. sarva s, ‘whole, all,’ Lat. sollus, ‘whole.’ — selig, in the adjs., just as trübselig, saumselig, and mühselig, has nothing to do with OHG. sâlîg, since it is a suffix of the neuts. Trübsal, Saumsal, Mühsal. In substs. of this kind -sal itself is a suffix formed from OHG. isal (gen. -sles), which appears in Goth. as -isl, n.