qualification vs fitness

qualification and fitness both are nouns.

Word	Noun	Adjective	Verb	Adverb
qualification	Yes	No	No	No
fitness	Yes	No	No	No

As nouns, fitness is a hypernym of qualification; that is, fitness is a word with a broader meaning than qualification:

qualification: an attribute that must be met or complied with and that fits a person for something
fitness: the quality of being suitable

Other hypernyms of qualification include fittingness.

qualification (noun)	fitness (noun)
the act of modifying or changing the strength of some idea	the quality of being suitable
an attribute that must be met or complied with and that fits a person for something	the quality of being qualified
a statement that limits or restricts some claim	good physical condition; being in shape or in condition