Johnny-jump-up vs viola

Johnny-jump-up and viola both are nouns.

Word	Noun	Adjective	Verb	Adverb
Johnny-jump-up	Yes	No	No	No
viola	Yes	No	No	No

As nouns, viola is a hypernym of Johnny-jump-up; that is, viola is a word with a broader meaning than Johnny-jump-up:

Johnny-jump-up: a common and long cultivated European herb from which most common garden pansies are derived
viola: any of the numerous plants of the genus Viola

Johnny-jump-up (noun)	viola (noun)
common violet of the eastern United States with large pale blue or purple flowers resembling pansies	any of the numerous plants of the genus Viola
a common and long cultivated European herb from which most common garden pansies are derived	a bowed stringed instrument slightly larger than a violin, tuned a fifth lower