Yours, Etc.: Origins and Uses of 8 Sign-Offs
late 14c., "to choke, suffocate, drown," of uncertain origin, possibly an alteration of Old French estouffer "to stifle, smother," which may be from a Germanic source (cf. Old High German stopfon "to plug up, stuff"). Metaphoric sense is from 1570s. Related: Stifled; stifling.