Definition: feeling remorse or regret
Every one of us has, on some occasion, felt like we should be saying “I’m sorry,” and wished to do so ... but without actually having to utter those dread words. If you would like to say that you are sorry, or have feelings of regret or remorse, but want to do so in a fashion that is sufficiently obscure that the person to whom you are apologizing doesn’t quite understand you, then compunctious is the word for you.
He was puzzled about Agnes, whose meaning he did not divine, and he was compunctious about Jack, to whom he could not wish a lover’s reward for his trouble.
—Margaret Oliphant, Agnes, 1866