self-command vs willpower

self-command and willpower both are nouns.

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

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

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

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

self-command (noun)	willpower (noun)
the trait of resolutely controlling your own behavior	the trait of resolutely controlling your own behavior