(intransitive) To become straight, or straighter / (transitive, intransitive) to steer straight / (intransitive) to sit up straight, to stop hunching. / (transitive) to deal with; put in order

To cease laughing or smiling, etc., and compose one's features.

(colloquial) To start behaving properly; get one's act together.

(archaic) Third-person singular simple present indicative form of straighten

(archaic) second-person singular simple present form of straighten