Denshi Jisho — Online Japanese dictionary

Couldn't find anything for 開けよう, so trying 開ける instead.

開ける あける 1: to open (a door, etc.); to unwrap (e.g. parcel, package);
2: to open (for business, etc.);
3: to empty; to clear out; to make space; to make room;
4: () to dawn; to grow light;
5: to end
Common word, Ichidan verb, Transitive verb 
開ける ひらける 1: to become opened up; to improve; to get better;
2: to develop; to progress; to become civilized (civilised); to be up-to-date;
3: to be enlightened; to be sensible
Common word, Ichidan verb, Intransitive verb 
開ける はだける 1: (Usually written using kana alone) to open; to bare; to expose;
2: to stretch
Ichidan verb, Transitive verb 

You can also

Look up kanji details for 開ける.

Try a Yahoo Jisho search for 開ける .
Try a Goo Jisho search for 開ける .
Try a Google search for 開ける .