Smack rat. A person who has an appearance strikingly similar to that of a rat and just so happened to partake in copious amounts of
smack (opioids)
Often a cold hearted fellow who would give their left arm for a packet of baccy and a spam fritter.
(Say in a vicious and raspy voice as an
insult)
Person-Here, I wish they would
stop being so horrible
Person 2-
Don't worry mate, they're a fucking
Smack Rat