Civil contempt is a coercive measure, see In re C.W., 169 Vt. 512, 739 A.2d 1236, 1239 (1999), which is necessarily discretionary. See Spabile v. Hunt, 134 Vt. 332, 334, 360 A.2d 51, 52 (1976). In comparison to criminal contempt, where the court's purpose is to punish, the court using civil contempt seeks to compel compliance with a court order. Imprisonment of indefinite duration may be the means to compel a party to do some act ordered by the court, and the party must be released on compliance with the order. Cf. In re Sage, 115 Vt. 516, 517, 66 A.2d 13, 14 (1949). We have characterized civil contempt as follows: Only compensatory fines or coercive sanctions may be imposed on a civil contemnor, and these must be purgeable, i.e., they must be capable of being avoided by defendants through adherence to the court's order. Thus, it is commonly said that the contemnor holds the keys to the jail and stands committed only until the act required by the court is performed. Russell v. Armitage, 166 Vt. 392, 407-08, 697 A.2d 630, 640 (1997) (Morse, J., concurring).