| Idiom | Meaning | Example | 
| fever breaks | 
fever stops, fever begins to go down
 | 
His fever broke last night. He's going to be alright.
 | 
| few and far between | 
very few, rare, the odd one
 | 
Canada still has timber wolves, but they are few and far between.
 | 
| fib | 
small lie, white lie
 | 
"What's a fib, Dad?" "It's a lie. It's the same as a lie."
 | 
| Fibber McGee's closet | 
a closet or cupboard so full of stuff that some of it falls out when the door is opened, everything but the kitchen sink
 | 
My brain is like Fibber McGee's closet. If you ask me a question, a whole bunch of stuff comes tumbling out!
 | 
| fickle finger of fate | 
(See the fickle finger of fate)
 | 
 | 
| fiddlesticks | 
oh no, darn, nuts, rats, shucks
 | 
Fiddlesticks! I forgot to get the mail!
 | 
| fido | 
effort, drive, get the lead out
 | 
I wouldn't say he's lazy, but he needs more fido!
 | 
| fifth business | 
an unimportant player, an extra member
 | 
You are fifth business, Dunny. Anyone can play your part.
 | 
| fifth column | 
an inside group of supporters of an outside force, possibly traitors;
the fifth column
 | 
Our children prevented our divorce. They knew who was causing
our breakup - they were like a fifth column!
 | 
 | definition provided by Claudia Crowley
 | 
| fifth wheel | 
(See a fifth wheel)
 | 
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