Facts of life
The facts about sex or marriage or birth that one should know.The boy is too young to know about the facts of life.
Fact of the matter
The truth is, the most important thing is.The fact of the matter is that we must finish the project this week.
Face value
The truth of something on the surface.The woman is a very nice person but you must take what she says at face value.
Face value
The value or price printed on a stamp/bond/paper money etc..I sold the postage stamps at their face value.
Face up to (something)
To accept something that is not easy to accept.My friend must face up to the fact that he will never have enough money to buy a car.
Face to face
In person.I had a face-to-face meeting with my supervisor to talk about my job performance.
Face the music
To accept the consequences of something.The boy must face the music for his actions very soon.
Face down (someone)
To confront someone boldly, to defy someone.We decided to face down our competitors and try to stay in business.
Fit in with (someone or something)
To be comfortable or in harmony with someone or something.The new boy fits in with the other children very well.
Fit for a king
To be totally suitable (just like for a king).The food at the wedding was fit for a king.