What is the meaning of Hangover?

Negative effects, such as headache or nausea, caused by previous drunkenness due to (excessive) consumption of alcohol.

Similar negative effects caused by previous excessive consumption of another substance, such as a drug, coffee, sugar, etc.

An unpleasant relic left from prior events.

A sleeping arrangement, usually in homeless shelters, over a rope.

Source: wiktionary.org