rocket scientist vs thinker

rocket scientist and thinker both are nouns.

Word	Noun	Adjective	Verb	Adverb
rocket scientist	Yes	No	No	No
thinker	Yes	No	No	No

As nouns, thinker is a hypernym of rocket scientist; that is, thinker is a word with a broader meaning than rocket scientist:

rocket scientist: a clever thinker
thinker: someone who exercises the mind (usually in an effort to reach a decision)

rocket scientist (noun)	thinker (noun)
an engineer who builds and tests rockets	an important intellectual
a clever thinker	someone who exercises the mind (usually in an effort to reach a decision)