What is "straighten up"

vb. 1 (context intransitive English) To become straight, or straighter 2 (context ambitransitive English) to steer straight 3 (context intransitive English) to sit up straight, to stop hunching. 4 (context transitive English) to deal with; put in order 5 (context transitive English) to tidy; tidy up 6 (context transitive English) To clarify 7 (context intransitive English) to start living a reformed life

v. straighten oneself; "He drew himself up when he talked to his superior" [syn: draw up, pull up]