Some words can be explosive in a bad way. I am reasonably sure you could say, in a story or a review, that someone reneged.
past tense: reneged; past participle: reneged
go back on a promise, undertaking, or contract.
"the administration had reneged on its election promises"
synonyms: default on, fail to honor, go back on, break, back out of, withdraw from, retreat from, welsh on, backtrack on; break one's word/promise about
"he reneged on his campaign promises"
On the other hand it would be something you shouldn't say if you called him a reneger. Just say it if you wonder about my point. (renigger)