Lexical Definition

‎כָּתַם‎ kâtham (kaw-tham') be stained ^H:V
a primitive root

mark.

• properly, to carve or engrave, i.e. (by implication) to inscribe indelibly

1) (Niphal) to be stained, be defiled, be deeply stained

Brown-Driver-Briggs

[‎כָּתַם‎] verb only Niph`al be stained (Late Hebrew Niph`al id. (Jastr); ‎כֶּתֶם‎ blood-stain; ᵑ7 ‎כְּתִים‎ (blood-)stained Isa 1:18 ‎כִּיתְמָא‎ blood-stain Jer 2:22 Syriac stain, defile, Participle, also Pa`el, Ethpa`al, and derive.; Arabic is cover, conceal, so Assyrian katâmu; Zinjirli ‎כתם‎ (?) DHM^{Sendsch. P. 37}); —

Niph`al Participle, figurative, ‎נִכְתָּם עֲוֺנֵךְ לְפָנַי‎ Jer 2:22 stained is thine iniquity before me (compare English phrase iniquity of deepest dye).

Brown-Driver-Briggs References