An abbreviation for the words, ‘Keep yourself safe’. Would be normally used from someone who cares truly about who they are saying this to. For one example..
(person1 says something negative to pers2)
pers2 “You should really kys (keep yourself safe) (person2 in this case knows person1 is being negative but person2 is nice and tells person1 to keep themselves safe.)
"kill yourself" or its a known person on discord.com! | kys#0008
you should kys.
Anne: I jus don't want to live (as a joke)
Frank: then jus kys (as a joke)
Anne: *laughing
"Son, what does kys mean"
"It means keep yourself safe"
"ok son remember to kys"