once-over vs examination

once-over and examination both are nouns.

Word	Noun	Adjective	Verb	Adverb
once-over	Yes	No	No	No
examination	Yes	No	No	No

As nouns, examination is a hypernym of once-over; that is, examination is a word with a broader meaning than once-over:

Other hypernyms of once-over include scrutiny.

once-over (noun)	examination (noun)
a swift cursory examination or inspection	the act of examining something closely (as for mistakes)
	the act of giving students or candidates a test (as by questions) to determine what they know or have learned
	a detailed inspection of your conscience (as done daily by Jesuits)
	a set of questions or exercises evaluating skill or knowledge
	formal systematic questioning