adjective.
Capable of being defeated, terminated, annulled, voided or invalidated.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adjective.
capable of being annulled or voided or terminated
Word Usage
"Besides being fallible, it seems that a priori justification is defeasible, that is, all-things-considered a priori justification can be defeated by further evidence."