Intelligent, intitive.
If they are an idiot, you could call them an imbecile or ignoramus. All three mean more or less the same thing.
Also try: inane, insane, irritating, insufferable, ingrate, inferior, infidel, insignificant, ill-bred, or intellectually deficient.
good?
You can call someone who is wise and has good sense as a sage or a wise person.
good
quota
Exceptional
beneficial
har,
Amulet
Munching on good food.
nerdnightname
intimate
Nice.