1. comparative form of stupid; less intelligent or more foolish
Usage: informal; sometimes considered nonstandard; ‘more stupid’ is preferred in formal writing

Examples

• That was even stupider than your last idea.
• I felt stupider after making that mistake.
• The second movie was stupider than the first one.
• Don’t do anything stupider than what you’ve already done.
• Each decision seemed stupider than the last.
• The plan got stupider as more people added suggestions.