The following example is taken from the book “Angels & Demons” (by Dan Brown).
‘So we do nothing?’ Vittoria felt compunction challenging a man in such frail health, but the director was so far out of line she didn’t even know him anymore.
compunction – definition and meaning of compunction by the Free Online Dictionary, Thesaurus and Encyclopedia (with audio pronunciation):
1. A strong uneasiness caused by a sense of guilt.
2. A sting of conscience or a pang of doubt aroused by wrongdoing or the prospect of wrongdoing.