reneg
rɪˈnɛɡ, rɪˈneɪɡ
Definitions
1. verb
to go back on one’s word, abandon a cause, or betray a trust
“The politician was accused of reneging on his campaign promises.”
2. noun
a person who goes back on their word or abandons a cause
“The company was criticized for hiring a former executive who was known as a reneg.”