hiss vs sibilate

hiss is a noun but sibilate is not a noun.

Word	Noun	Adjective	Verb	Adverb
hiss	Yes	No	Yes	No
sibilate	No	No	Yes	No

As verbs, hiss and sibilate are synonyms defined as:

hiss and sibilate: make a sharp hissing sound, as if to show disapproval

Other synonyms of hiss include siss, sizz.

As verbs, hiss and sibilate are synonyms defined as:

Other synonyms of hiss include siss, sizz.

hiss (noun)	sibilate (noun)
a cry or noise made to express displeasure or contempt
a fricative sound (especially as an expression of disapproval)

hiss (verb)	sibilate (verb)
make a sharp hissing sound, as if to show disapproval	make a sharp hissing sound, as if to show disapproval
express or utter with a hiss	express or utter with a hiss
show displeasure, as after a performance or speech	utter a sibilant
move with a whooshing sound	pronounce with an initial sibilant