unbelieving vs skeptical

unbelieving and skeptical both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unbelieving	No	Yes	No	No
skeptical	No	Yes	No	No

As adjectives, unbelieving and skeptical are synonyms defined as:

unbelieving and skeptical: denying or questioning the tenets of especially a religion

Other synonyms of unbelieving include disbelieving, sceptical.

unbelieving (adjective)	skeptical (adjective)
holding that only material phenomena can be known and knowledge of spiritual matters or ultimate causes is impossible	marked by or given to doubt
denying or questioning the tenets of especially a religion	denying or questioning the tenets of especially a religion
rejecting any belief in gods