Changeable
Part of speech: adjective
Definition: Capable of being changed. Subject to sudden or frequent changes.
Example sentence: We want to make sure that nobody has an advantage over us based on laws that are easily changeable.
Uncertain
Part of speech: adjective
Definition: not known for certain; questionablenot yet determined; undecidedvariable and subject to changefitful or unsteadyunpredictable or capricious
Example sentence: We always live in an uncertain world. What is certain is that the United States will go forward over time.