annex vs supplement

annex and supplement both are nouns.

Word	Noun	Adjective	Verb	Adverb
annex	Yes	No	Yes	No
supplement	Yes	No	Yes	No

As verbs, supplement is a hypernym of annex; that is, supplement is a word with a broader meaning than annex:

Other hypernyms of annex include add on, affix, append.

annex (noun)	supplement (noun)
an addition that extends a main building	a supplementary component that improves capability
	a quantity added (e.g. to make up for a deficiency)
	textual matter that is added onto a publication; usually at the end

annex (verb)	supplement (verb)
add an extra part to	add to the very end
take (territory) as if by conquest	add as a supplement to what seems insufficient
	serve as a supplement to