stance vs posture

stance and posture both are nouns.

Word	Noun	Adjective	Verb	Adverb
stance	Yes	No	No	No
posture	Yes	No	Yes	No

As nouns, posture is a hypernym of stance; that is, posture is a word with a broader meaning than stance:

Other hypernyms of stance include attitude, position.

As nouns, stance and posture are synonyms defined as:

Other synonyms of stance include position.

stance (noun)	posture (noun)
standing posture	the arrangement of the body and its limbs
a rationalized mental attitude	characteristic way of bearing one's body
	capability in terms of personnel and materiel that affect the capacity to fight a war
	a rationalized mental attitude

stance (verb)	posture (verb)
	assume a posture as for artistic purposes
	behave affectedly or unnaturally in order to impress others