Ambidextrousness, Ambidexterity

Both Ambidextrousness and Ambidexterity are real words.

Ambidextrousness is given as:
1. The quality of being ambidextrous; ambidexterity
2. the property of being equally skillful with each hand

while Ambidexterity is given as:
1. The state or quality of being ambidextrous
2. Deceit or hypocrisy