freethinking vs philosophy

freethinking and philosophy both are nouns.

Word	Noun	Adjective	Verb	Adverb
freethinking	Yes	No	No	No
philosophy	Yes	No	No	No

As nouns, philosophy is a hypernym of freethinking; that is, philosophy is a word with a broader meaning than freethinking:

freethinking: the doctrine that reason is the right basis for regulating conduct
philosophy: a belief (or system of beliefs) accepted as authoritative by some group or school

Other hypernyms of freethinking include doctrine, ism, philosophical system, school of thought.

freethinking (noun)	philosophy (noun)
the doctrine that reason is the right basis for regulating conduct	the rational investigation of questions about existence and knowledge and ethics
	a belief (or system of beliefs) accepted as authoritative by some group or school
	any personal belief about how to live or how to deal with a situation