stupid
stu-pid
adjective
Lacking intelligence or common sense; showing poor judgement or understanding.
"Don't be so stupid; think before you act."
Thesaurus
Synonyms: headless, brainless, unintelligent, cloddish, foolish, derp, dull, blockheaded, duncical, unthinking, gaumless, asinine
Antonyms: intelligent, smart