This is one of the words most mentioned in the Quran, yet it is hard to translate. Often it is translated "to disbelieve," which is technically correct but not always. Literally, it means to cover something up. It is used for disbelief because God teaches us that faith in Him is an innate knowledge we are all born with and to develop disbelief requires conscious denial of what each of us knows in his or her heart to be the truth.
In several verses in the Quran, the verb
كفر is contrasted with the verb
شكر (to thank or to be grateful). For instance:
Thus a reasonable translation of
كفر would be "to be ungrateful." See
this topic for further discussion and examples.
Question is: Can we uniformly translate it that way, or should we use the traditional translation of "to disbelieve" at times?