headshake vs motility

headshake and motility both are nouns.

Word	Noun	Adjective	Verb	Adverb
headshake	Yes	No	No	No
motility	Yes	No	No	No

As nouns, motility is a hypernym of headshake; that is, motility is a word with a broader meaning than headshake:

headshake: the act of turning your head left and right to signify denial or disbelief or bemusement
motility: a change of position that does not entail a change of location

Other hypernyms of headshake include motion, move, movement.

headshake (noun)	motility (noun)
the act of turning your head left and right to signify denial or disbelief or bemusement	a change of position that does not entail a change of location
	ability to move spontaneously and independently