Simple-minded
Part of speech: adjective
Definition: Lacking subtlety or sophistication Lacking mental capacity; feeble-minded
Retarded
Part of speech: verb
Definition: Past tense of retard; slowed.Past participle of retard; slowed.
Part of speech: adjective
Definition: Delayed in development.Of a person, having mental retardation.By extension, of a person or thing, stupid; senseless; irrational.Under the influence of alcohol.