decubitus vs posture

decubitus and posture both are nouns.

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

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

Other hypernyms of decubitus include attitude, position.

decubitus (noun)	posture (noun)
a reclining position (as in a bed)	the arrangement of the body and its limbs
	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

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