From qarah; an (unfortunate) occurrence, i.e. Some accidental (ceremonial) disqualification -- uncleanness that chanceth.
see HEBREW qarah
H7137. qareh
[קָרֶה] noun [masculine] chance, accident; — construct לַיְלַה מִקְּרֵה Deuteronomy 23:11 by reason of the chance of the night (i.e.nocturnal pollution, compare Leviticus 15:16).