I came across this word while reading and did not know what the writer was trying conveying, so off to the dictionary I went to learn about the word. Since is was new to me, I thought others might enjoy exposure to the word.

defeasible

MEANING:

adjective: Capable of being revised, defeated, or annulled.

ETYMOLOGY:

From Old French desfaire (to undo or destroy), from Latin dis- (apart, away) + facere (to do). Ultimately from the Indo-European root dhe- (to set or put), which is also the source of do, deed, factory, fashion, face, rectify, defeat, sacrifice, satisfy, Sanskrit sandhi (joining), Urdu purdah (veil or curtain), and Russian duma (council). Earliest documented use: 1586.

USAGE:

“Surely many moral duties are defeasible, and in that sense relative. We all recognize that although lying is typically wrong, under certain circumstances — to protect someone’s life, for example — it is justifiable.”
Austin Dacey; Believing in Doubt; The New York Times; Feb 3, 2006.