affix vs append

affix is a noun but append is not a noun.

Word	Noun	Adjective	Verb	Adverb
affix	Yes	No	Yes	No
append	No	No	Yes	No

As verbs, affix and append are synonyms defined as:

Other synonyms of affix include add on, supplement.

affix (noun)	append (noun)
a linguistic element added to a word to produce an inflected or derived form

affix (verb)	append (verb)
stick or fasten to	state or say further
add to the very end	fix to; attach
attach or become attached to a stem word	add to the very end