Denshi Jisho — Online Japanese dictionary

こく 1: archaic period of time (usu. a period of approx. two hours corresponding to one of the signs of the Chinese zodiac);
2: victory;
3: strictness; cruelty
Noun 
そうこく rivalry
Noun, Suru verb 

You can also

Look up kanji details for *剋.

Try a Yahoo Jisho search for *剋 .
Try a Goo Jisho search for *剋 .
Try a Google search for *剋 .