foolish

1, 2 senseless, vacant, vapid, simple, witless. Foolish, fatuous, silly, inane, stupid, asinine imply weakness of intellect and lack of judgment. Foolish implies lack of common sense or good judgment or, sometimes, weakness of mind: a foolish decision; The child seems foolish. Fatuous implies being not only foolish, dull, and vacant in mind, but complacent and highly self-satisfied as well: fatuous and self-important; fatuous answers. Silly denotes extreme and conspicuous foolishness; it may also refer to pointlessness of jokes, remarks, etc.: silly and senseless behavior; a perfectly silly statement. Inane applies to silliness that is notably lacking in content, sense, or point: inane questions that leave one no reply. Stupid implies natural slowness or dullness of intellect, or, sometimes, a benumbed or dazed state of mind; it is also used to mean foolish or silly: well-meaning but stupid; rendered stupid by a blow; It is stupid to do such a thing. Asinine originally meant like an ass; it applies to witlessly stupid conversation or conduct and suggests a lack of social grace or perception: He failed to notice the reaction to his asinine remarks.

1 imprudent, unreasonable, foolhardy, irrational; thoughtless, nonsensical, ridiculous, absurd, pointless, preposterous.