op·pos·a·ble 
(ə-pōzə-bəl)
(ə-pōzə-bəl)adj.
1. Possible to oppose or resist.
2. Capable of moving opposite to and touching one or more other digits of the same hand or foot in a way that allows grasping: The thumb is an opposable digit.
op·pos′a·bili·ty n.