Denshi Jisho — Online Japanese dictionary

無くなる なくなる to disappear; to get lost
Common word, Godan verb with ru ending, Intransitive verb 

You can also

Look up kanji details for 無くなる.

Try a Yahoo Jisho search for 無くなる .
Try a Goo Jisho search for 無くなる .
Try a Google search for 無くなる .