Speaking English Like A Native

a nightcap is a euphemism for an alcoholic drink taken just before the evening ends. it is often used in movies when a man or a woman invites someone to come into their home or apartment after an evening out of town, giving it strong sexual overtones. in essence, it mean to “cap of” an evening with a final drink.

example:

1. it’s still early! how about a nightcap?
2. you’re interested in more than just a nightcap, aren’t you!
3. your problem is that you have one nightcap after another!