flesh out vs alter

flesh out and alter both are verbs.

Word	Noun	Adjective	Verb	Adverb
flesh out	No	No	Yes	No
alter	No	No	Yes	No

As verbs, alter is a hypernym of flesh out; that is, alter is a word with a broader meaning than flesh out:

Other hypernyms of flesh out include change, modify.

flesh out (verb)	alter (verb)
become round, plump, or shapely	remove the ovaries of
add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing	become different in some particular way, without permanently losing one's or its former characteristics or essence
make fat or plump	cause to change; make different; cause a transformation
	insert words into texts, often falsifying it thereby
	make an alteration to