Orig: from an unused root meaning to set a period (compare 5710, 5749); the menstrual flux (as periodical); by implication (in plural) soiling:--filthy. H5710H5749
Use: TWOT-1564a Noun Feminine
Grk Strong:
1) menstruation 1a) filthy rag, stained garment (fig. of best deeds of guilty people)