Stupid, dull, dense, crass, dumb mean lacking in power to absorb ideas or impressions. Stupid implies a slow-witted or dazed state of mind that may be either congenital or temporary. If you say that someone or something is stupid, you mean that they show a lack of good judgment or intelligence and they are not at all sensible.
I'll never do anything so stupid again. Definition of stupid adjective in oxford advanced learner's dictionary. Stupid is an adjective used to describe someone or something that lacks intelligence, common sense, or is considered foolish or irrational.
Jan 20, 2026adjective stupid (comparative stupider or more stupid, superlative stupidest or most stupid) without intelligence. The word comes from a latin adjective that means “amazed or stunned,” and stupid people are stunned by everything because their minds are numb. You can make a stupid mistake when you’re not.