Able to use both hands equally well (12)
I believe the answer is:
ambidextrous
'able to use both hands equally well' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ambidextrous that I've seen before include "Equally expert with both hands" , "Highly adept" , "Good with either hand" , "Able to use either hand equally well" , "Using both hands" .)