Little lie (3)
I believe the answer is:
fib
'little lie' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for fib that I've seen before include "Story" , "A harmless white lie" , "minor piece of fiction" , "One must be 20 [UNTRUE]" , "Petty falsehood" .)