slit vs incision

slit and incision both are nouns.

Word	Noun	Adjective	Verb	Adverb
slit	Yes	No	Yes	No
incision	Yes	No	No	No

As nouns, slit and incision are synonyms defined as:

Other synonyms of slit include dent, prick, scratch.

slit (noun)	incision (noun)
a long narrow opening	the cutting of or into body tissues or organs (especially by a surgeon as part of an operation)
obscene terms for female genitals	a depression scratched or carved into a surface
a narrow fissure
a depression scratched or carved into a surface

slit (verb)	incision (verb)
cut a slit into
make a clean cut through