1.Not proper; not suitable; not fitted to the circumstances, design, or end; unfit; not becoming; incongruous; inappropriate; indecent; as, an improper medicine; improper thought, behavior, language, dress. "Follow'd his enemy king, and did him service, Improper for a slave." "And to their proper operation still, Ascribe all Good; to their improper, Ill."
2.Not peculiar or appropriate to individuals; general; common. (Obs.) "Not to be adorned with any art but such improper ones as nature is said to bestow, as singing and poetry."
3.Not according to facts; inaccurate; erroneous.