spoil vs foul up

spoil is a noun but foul up is not a noun.

Word	Noun	Adjective	Verb	Adverb
spoil	Yes	No	Yes	No
foul up	No	No	Yes	No

As verbs, spoil and foul up are synonyms defined as:

spoil (noun)	foul up (noun)
the act of stripping and taking by force
the act of spoiling something by causing damage to it
(usually plural) valuables taken by violence (especially in war)

spoil (verb)	foul up (verb)
become unfit for consumption or use	make a mess of, destroy or ruin
alter from the original
make imperfect
destroy and strip of its possession
have a strong desire or urge to do something
hinder or prevent (the efforts, plans, or desires) of
treat with excessive indulgence
make a mess of, destroy or ruin