Old English ælmihtig "all-powerful," also a by-name of God; compound of æl (see all) + mihtig (see mighty); common Germanic (cf. Old Saxon alomahtig, Old High German alamahtic, German allmächtig, Old Norse almattigr), perhaps an early Germanic loan-translation of Latin omnipotens (see omnipotent).
The almighty dollar, that great object of universal devotion throughout our land." [Washington Irving, 1836]Related: Almightily.
Enormous: There was an almighty fuss (1820s+)