Face the music
Accept the negative consequences of something
Face to face
Seeing each other (usually use in a meeting).
Face value
Interest in appearance more than the detail inside
Fair and square
Very fair
Fall between two stools
Something try to be two things but is not good at being either
Fancy man
new lover
Fat cat
Very rich person
Fat head
Stupid person
Feed someone a line
trick someone
Feel blue
Feel sad
Feel like a million dollar
Feel very good
Feeling a bit under the weather
Feeling a bit sick
Fishy smell
Something strange
Flea market
A Market where sells second hand goods
Flood the market
Too much supply (products or services) in the market.
Fly a kite
Test reaction of the idea
Fly blind
Work without training or instruction
Follow one's nose
Strictly follow one's direction.
Food for thought
Something to think about
For ages
Very long time
For the birds
Something which are not interesting
Fork over
Give / offer