category vs concept

category and concept both are nouns.

Word	Noun	Adjective	Verb	Adverb
category	Yes	No	No	No
concept	Yes	No	No	No

As nouns, concept is a hypernym of category; that is, concept is a word with a broader meaning than category:

category: a general concept that marks divisions or coordinations in a conceptual scheme
concept: an abstract or general idea inferred or derived from specific instances

Other hypernyms of category include conception, construct.

category (noun)	concept (noun)
a general concept that marks divisions or coordinations in a conceptual scheme	an abstract or general idea inferred or derived from specific instances
a collection of things sharing a common attribute