According to the majority of jurists, there is no difference between fard and wajib, except in the Pilgrimage (Hajj), where non-performance of a wajib does not invalidate the pilgrimage, but necessitates expiation by slaughtering.
However, the Hanafi jurists hold that there is a difference between the fard and the wajib. They maintain that the fard is that which the Lawgiver strictly requires to be done, and whose obligatory character is proved by definitive evidence, whereas the wajib is that which has been proved by speculative evidence.
Someone who denies the fard is considered a kafir (disbeliever), as he or she is denying what has been ordained by clear-cut and decisive texts. However, someone who denies the wajib is not considered a disbeliever but as fasiq (disobedient). To illustrate, someone who denies the five daily prayers is considered a disbeliever because they are fard, while one who denies the witr prayer, which is wajib in the Hanafi School, is not considered a disbeliever.