self-command vs self-possession

self-command and self-possession both are nouns.

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

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

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

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

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