verb

• (intransitive) To hurt or sting.
  "After being hit with a pitch, the batter exclaimed "Ouch, my arm smarts!""
• (transitive) To cause a smart or sting in.
  "A goad that […] smarts the flesh."
• (intransitive) To feel a pungent pain of mind; to feel sharp pain or grief; to be punished severely; to feel the sting of evil.
  "You think this cruel? take it for a rule, / No creature ſmarts ſo little as a Fool."

adj

• (informal) Exhibiting intellectual knowledge, such as that found in books.
• (often in combination) Equipped with intelligent behaviour (digital/computer technology).
  "smart car"
• (Southern US, dated) Intense in feeling; painful. Used usually with the adverb intensifier right.
  "He raised his voice; it hurt her feelings right smart."
• (archaic) Efficient; vigorous; brilliant.
  "The stars shine smarter."

noun

• (slang, dated) A dandy; one who is smart in dress; one who is brisk, vivacious, or clever.
  "[…] I reſolved to quit all further Converſation vvith Beaus and Smarts of all kinds, […]"

noun

• (computer hardware) Acronym of self-monitoring, analysis and reporting technology; also S.M.A.R.T.: a monitoring system included in computer HDDs and SSDs in order to detect and report various indicators of drive reliability with the intent of anticipating imminent hardware failures.