Denshi Jisho — Online Japanese dictionary

愚か おろか foolish; stupid
Common word, Na-adjective, Noun 
愚か おろかもの fool
Noun 
愚かしい おろかしい foolish; stupid
Adjective 

You can also

Look up kanji details for 愚か.

Try a Yahoo Jisho search for 愚か .
Try a Goo Jisho search for 愚か .
Try a Google search for 愚か .