mid-15c., "not properly mixed, undiluted," from un- (1) "not" + past participle of temper (v.). Similar formation in Middle Dutch ongetempert, Middle High German ungetempert. Earlier as "unrestrained" (late 14c.), also, of a musical instrument, "not properly tuned;" meaning "unhardened" is from 1820.
双语例句
1. Overheating can result in tempered martensite ( OTM ) or untempered martensite ( UTM ) formations in the base metal.
