slit (v.) Look up slit at Dictionary.com
Old English slitan "cut or tear up, slit," from Proto-Germanic *slitanan (cf. Old Saxon slitan, Old Norse slita, Middle Low German, Middle Dutch sliten, Dutch slijten, Old High German slizan, German schleißen "to slit"). Slit skirt is attested from 1913.
slit (n.) Look up slit at Dictionary.com
mid-13c., from slit (v.). Slang sense of "vulva" is attested from 1640s.