gibbousness vs nubble

gibbousness and nubble both are nouns.

Word	Noun	Adjective	Verb	Adverb
gibbousness	Yes	No	No	No
nubble	Yes	No	No	No

As nouns, nubble is a hyponym of gibbousness; that is, nubble is a word with a more specific, narrower meaning than gibbousness:

gibbousness: something that bulges out or is protuberant or projects from its surroundings
nubble: a small lump or protuberance

Other hyponyms of gibbousness include frontal eminence, occipital protuberance, belly, caput, mogul, nub, snag, wart.

gibbousness (noun)	nubble (noun)
something that bulges out or is protuberant or projects from its surroundings	a small lump or protuberance