clonus vs convulsion

clonus and convulsion both are nouns.

Word	Noun	Adjective	Verb	Adverb
clonus	Yes	No	No	No
convulsion	Yes	No	No	No

As nouns, convulsion is a hypernym of clonus; that is, convulsion is a word with a broader meaning than clonus:

clonus: convulsion characterized by alternating contractions and relaxations
convulsion: violent uncontrollable contractions of muscles

clonus (noun)	convulsion (noun)
convulsion characterized by alternating contractions and relaxations	a physical disturbance such as an earthquake or upheaval
	violent uncontrollable contractions of muscles
	a sudden uncontrollable attack
	a violent disturbance