checkup vs scrutiny

checkup and scrutiny both are nouns.

Word	Noun	Adjective	Verb	Adverb
checkup	Yes	No	No	No
scrutiny	Yes	No	No	No

As nouns, scrutiny is a hypernym of checkup; that is, scrutiny is a word with a broader meaning than checkup:

checkup: a thorough physical examination; includes a variety of tests depending on the age and sex and health of the person
scrutiny: the act of examining something closely (as for mistakes)

Other hypernyms of checkup include examination.

checkup (noun)	scrutiny (noun)
a thorough physical examination; includes a variety of tests depending on the age and sex and health of the person	the act of examining something closely (as for mistakes)
	a prolonged intense look