If you have to face the music, you have to accept the negative consequences of something you have done wrong.
A fairweather friend is the type who is always there when times are good but forgets about you when things get difficult or problems crop up.
Fall off a truck
If someone tries to sell you something that has fallen of the back of a truck they are trying to sell you stolen goods.
Fall on your sword
If someone falls on their sword, they resign or accept the consequences of some wrongdoing.
Familiarity breeds contempt
This means that the more you know something or someone, the more you start to find faults and dislike things about it or them.
Fat chance!
This idiom is a way of telling someone they have no chance.
Fat head
A fat head is a dull, stupid person.
Fat hits the fire
When the fat hits the fire, trouble breaks out.
Fat of the land
Living off the fat of the land means having the best of everything in life.
Fate worse than death
Describing something as a fate worse than death is a fairly common way of implying that it is unpleasant.
Feather in your cap
A success or achievement that may help you in the future is a feather in your cap.
Feel at home
If you feel relaxed and comfortable somewhere or with someone, you feel at home.
Feel free
If you ask for permission to do something and are told to feel free, the other person means that there is absolutely no problem
Feeling Blue
If you feel blue, you are feeling unwell, mainly associated with depression or unhappiness.
Feet on the ground
A practical and realistic person has their feet on the ground.