expression vs blowup

expression and blowup both are nouns.

Word	Noun	Adjective	Verb	Adverb
expression	Yes	No	No	No
blowup	Yes	No	No	No

As nouns, blowup is a hyponym of expression; that is, blowup is a word with a more specific, narrower meaning than expression:

Other hyponyms of expression include lamentation, mourning, act, ebullition, effusion, gush, outburst.

expression (noun)	blowup (noun)
the act of forcing something out by squeezing or pressing	a photographic print that has been enlarged
the feelings expressed on a person's face	an unrestrained expression of emotion
a word or phrase that particular people use in particular situations	a violent release of energy caused by a chemical or nuclear reaction
the style of expressing yourself
expression without words
a group of symbols that make a mathematical statement
the communication (in speech or writing) of your beliefs or opinions
a group of words that form a constituent of a sentence and are considered as a single unit
(genetics) the process of expressing a gene