i-adjective
feel guilty; have a guilty conscience; have qualms
Describes a feeling of guilt or unease about something one has done or is doing. Often used in the negative form やましくない to assert a clear conscience.
彼は何もやましいことはしていない。
He hasn't done anything to feel guilty about.
やましい気持ちでいっぱい
I was filled with a guilty feeling.