sombody that is really paranoid when they are ''high,stoned,baked,''.
or also can be used when a person acts stupid when they are ''high''.
ex1.sketch monkey: a dawg u got eye drops?
hommie: na dawggg but ur eyes are fuckin white geee??
sketch monkey: why do u have to lie!?
hommie: I iant dawg ur eyes are white!, u fuckin ''sketch monkey'' lol.
hommie: are u ganna take a hit rite here in class??
sketch monkey: yea why not??
hommie: dawg ur a ''sketch monkey'' ur ganna get cought up.
sketch monkey: hommie ur a ''sketch monkey'' nothings ganna happen mr.teacher is old he wont smell shit.
a homo sapien who appears to be quite sketch, regardless of age, race, or gender...
DUDE, that guy was a real SKETCH MONKEY... It' hard to believe they let him be a cop.