hammock vs knoll

hammock and knoll both are nouns.

Word	Noun	Adjective	Verb	Adverb
hammock	Yes	No	No	No
knoll	Yes	No	No	No

As nouns, hammock and knoll are synonyms defined as:

Other synonyms of hammock include hillock, hummock, mound.

hammock (noun)	knoll (noun)
a hanging bed of canvas or rope netting (usually suspended between two trees); swings easily	a small natural hill
a small natural hill