To stab someone with a bladed object.
Ghetto slang used by London roadmen, gangsters, yardies.
From the term wet - to make bleed.
"see this shiv geezer, man's gonna whet you bruv"
The number one adlib for widely known rap goat Playboi Carti
Im with dro, got that pack goin for the low
(Whet, whet).