Answer: mutable

AnswerCrossword Clue
MUTABLEApt to morph
MUTABLEChameleonlike
MUTABLECapable of change
MUTABLEFluid
MUTABLENot set in stone
MUTABLESubject to change
MUTABLENot fixed
mutablecapable of change
mutablegiven to changing; fickle or inconstant.
mutablesubject to change