Meaning

noun a smoky fire to drive away insects

noun a blemish made by dirt

verb make a smudge on; soil by smudging

originFrom Middle English *smogen (attested in the gerund smogynge (“soiling, smudging”)), of obscure origin. Compare Middle English besmudded, bismuddet (“filthy”), Middle English smod (“filth, obscene behaviour”), Middle Dutch smoddich (“filthy, dirty”), German schmutzig (“dirty, filthy”).

Etymology from Wiktionary, CC BY-SA 3.0