1. subject to alteration or change
; - Example: "the death sentence was commutable to life imprisonment"
2. capable of being exchanged for another or for something else that is equivalent
; [syn: commutable, substitutable]
The Collaborative International Dictionary of English v.0.48:
Commutable \Com*mut"a*ble\, a. [L. commutabilis.]
Capable of being commuted or interchanged.
The predicate and subject are not commutable.