smart

Old English
of an instrument, such as a rod, whip, etc.: "inflicting or causing pain; biting, stinging"
of a weapon: "sharp and cutting"

Middle English
of pain (physical or mental), sorrow, etc.: "sharp, keen, painful, severe. Also of wounds or other cause of discomfort"
of speech or words: "harsh, injurious, unpleasant"

related to smeortan "be painful"