c.1200, "to suffocate with smoke," from smother (n.), earlier smorthre "dense, suffocating smoke" (late 12c.), from stem of Old English smorian "to suffocate, choke, strangle, stifle," cognate with Middle Dutch smoren, German schmoren; possibly connected to smolder. Meaning "to kill by suffocation in any manner" is from 1540s; sense of "to extinguish a fire" is from 1590s. Sense of "stifle, repress" is first recorded 1570s; meaning "to cover thickly (with some substance)" is from 1590s. Related: Smothered; smothering.