As adjectives the difference between snitty and snithy
is that snitty is (informal) agitated or annoyed while snithy is sharp; cutting.
snitty
English
Adjective
(er)
(informal) Agitated or annoyed.
:There's no point getting snitty about the weather. snithy
English
Adjective
(en-adj)
Sharp; cutting.
(of wind or weather) Cold.