dodgy

'Dodgy' is an informal adjective that you can use to describe a person or a thing.

Describing something, it can mean 'risky' or 'dangerous' eg That electrical wiring looks a bit dodgy. I think it needs to be checked by an electrician before someone hurts themselves.
It can also mean 'unreliable' eg The tax inspector questioned what he regarded as dodgy accounts.

Also if you have been having problems with your stomach or digestion eg feeling a bit sick and needing to be careful what you eat, you can say you have a dodgy stomach (or tummy). 

A dodgy person can be someone who might be dishonest eg I didn't want to buy the car from him because he looked rather dodgy.