Dodgy = unreliable, uncertain, untrustworthy. A negative quality, but it varies a bit to fit the context.
Dodgy takeaway? It might make you bleed at both ends.
Dodgy beer probably tastes of vinegar.
A dodgy geezer sells dope or steals car radios.
Never play for money if your opponent has dodgy dice; and if you're handed a dodgy fiver, give 'em a smack in marf.
It's a very old concept. Apparently homo erectus
was dodgy at DIY.