self-control vs willpower

self-control and willpower both are nouns.

Word	Noun	Adjective	Verb	Adverb
self-control	Yes	No	No	No
willpower	Yes	No	No	No

As nouns, self-control and willpower are synonyms defined as:

self-control and willpower: the trait of resolutely controlling your own behavior

Other synonyms of self-control include possession, self-command, self-possession, self-will, will power.

self-control (noun)	willpower (noun)
the act of denying yourself; controlling your impulses	the trait of resolutely controlling your own behavior
the trait of resolutely controlling your own behavior