ass vs fundament

ass and fundament both are nouns.

Word	Noun	Adjective	Verb	Adverb
ass	Yes	No	No	No
fundament	Yes	No	No	No

As nouns, ass and fundament are synonyms defined as:

ass (noun)	fundament (noun)
slang for sexual intercourse	lowest support of a structure
hardy and sure-footed animal smaller and with longer ears than the horse	the fleshy part of the human body that you sit on
the fleshy part of the human body that you sit on	the fundamental assumptions from which something is begun or developed or calculated or explained
a pompous fool