1.
aftertaste (of food or drink)
The taste that lingers in the mouth after eating or drinking something.
2.
aftertaste (figurative), lingering impression
The feeling or impression that remains after an experience, event, or encounter. Often used negatively to describe an unpleasant lingering feeling.
Usage
The expression 後味が悪い (bad aftertaste) is extremely common in both literal and figurative senses. The opposite, 後味がいい / がよい, is also used but less frequent. In the figurative sense, it describes the emotional residue of an experience — particularly disagreements, moral dilemmas, or unsatisfying outcomes.