It's pretty similar to the American word 'dork' or 'nerd'
I. E. a stupid or ridiculous person; jerk; nerd.
also adjectival version: "cheeny"
similar again to 'dorky' meaning stupid, inept, or unfashionable
"Oh, you cheen!"
"Stop being a cheen!"
"Stop being so cheeny!"
"That suit is so cheeny
A second example, if attempting to pull in a nightclub and rejected.. say "cheen" point to the tip of your nose and walk away.
Not to be used for example if you just fell over and say
"I got cheened by the floor"
Person 2 -- "You talking Jib Deuce or Christmas Party?"
Person 1 -- "Christmas cheen of course."
Person 2 -- "I'm down but I gotta grab a few hundy."