· flaky
· He is too flaky to do the work.
· MEANING: unreliable (来源：http://www.EnglishCN.com)

· flashback
· At the wedding he had a flashback of his old girlfriend.
· MEANING: remembered

· flick
· I haven't seen a flick in a long time.
· MEANING: movie

· flip out
· He flipped out when he heard that his mother had been killed.
· MEANING: lost control

· flip side
· What kind of music do you have on the flip side of the tape?
· MEANING: other side

· fox
· His older sister is a fox.
· MEANING: very attractive

· foxy
· She is a foxy lady.
· MEANING: sexy

· freebie
· The pillow was a freebie
· MEANING: free

· get into something
· I got into gardening in high school.
· MEANING: became seriously interested in

· get it
· I listened to the joke twice, but I still don't get it.
· MEANING: understand

· get with it
· If you don't get with it, we will never finish this work.
· MEANING: hurry up