Minor falsehood (5,3)
I believe the answer is:
white lie
'minor falsehood' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for white lie that I've seen before include "A trivial fib" , "Supposedly helpful untruth" , "A harmless fib" , "Harmless untruth" , "An unimportant departure from of the truth" .)