Feeding Frenzy:
An aggressive attack on someone by a group.
Field Day:
An enjoyable day or circumstance.
Finding Your Feet:
To become more comfortable in whatever you are doing.
Finger lickin' good:
A very tasty food or meal.
Fixed In Your Ways:
Not willing or wanting to change from your normal way of doing something.
Flash In The Pan:
Something that shows potential or looks promising in the beginning but fails to deliver anything in the end.
Flea Market:
A swap meet. A place where people gather to buy and sell inexpensive goods.
Flesh and Blood:
This idiom can mean living material of which people are made of, or it can refer to someone's family.
Flip The Bird:
To raise your middle finger at someone.
Foam at the Mouth:
To be enraged and show it.
Fools' Gold:
Iron pyrites, a worthless rock that resembles real gold.
French Kiss:
An open mouth kiss where tongues touch.
From Rags To Riches:
To go from being very poor to being very wealthy.
Fuddy-duddy:
An old-fashioned and foolish type of person.
Full Monty:
This idiom can mean either, "the whole thing" or "completely nude".
Funny Farm:
A mental institutional facility.
Idioms can be confusing - Enjoy!