If someone wakes up with a hangover, they feel sick and have a headache because they have drunk a lot of alcohol the night before.
N-COUNT
遺留觀念（或習俗）
Something that is a hangover from the past is an idea or way of behaving which people used to have in the past but which people no longer generally have.
例句
As a hangover from rationing, they mixed butter and margarine.作為食品配給制的一種遺留影響，他們總把黃油和人造黃油混在一起吃。