marah (Hebrew #4784)
to be (causatively, make) bitter (or unpleasant); (figuratively) to rebel (or resist; causatively, to provoke)
KJV usage: bitter, change, be disobedient, disobey, grievously, provocation, provoke(-ing), (be) rebel (against, -lious).
Pronounce: maw-raw'
Origin: a primitive root