K-P-R
K-P-R is a Semitic root, in Arabic and Hebrew rendered as K-F-R (in Arabic script: ك-ف-ر; in Hebrew script: כ-פ-ר).
The basic meaning of the root is "to cover", but it is used in the sense "to conceal" and hence "to deny", and its notability derives from its use for religious heresy or apostasy (as it were describing the "concealment" of religious truth) in both Islam and Judaism.
Arabic
Concepts
Kufr (Arabic: كفر), Kefirah (Hebrew: כְּפִירָה) — negation of the faith; disbelief
Kāfir (Arabic: كافر), pl. Kuffār (كفار) and Kāfirīn (كافرين), Kofer (Hebrew: כופר), pl. Kofrim (Hebrew: כופרים) — "coverer" — unbeliever; "a person who hides or covers the truth"
Takfīr (Arabic: تكفير) — excommunication
Mukaffir (Arabic: مكفر) — the act which precipitates takfīr
Kafare (Arabic) — sentence for a crime, for example lashes for adultery, used in religious issues
Kfar (Hebrew: כפר); kafr Arabic: كفر) — village
Kaffarah (Arabic: كفارة); Kofer (Hebrew: כופר) — compensation for damages in Quranic, Talmudic and Mishnaic tort law.