imprudent

Synonyms: brash careless foolhardy foolish heedless illadvised ill-considered ill-judged impolitic improvident incautious inconsiderate indiscreet inexpedient injudicious irresponsible leaving self wide open off the deep end overhasty playing with fire rash reckless temerarious thoughtless unadvisable unthinking unwise

Antonyms: careful cautious discreet prudent wise