While it circulates before start of election, it's not true (5,3)
I believe the answer is:
white lie
'it's not true' is the definition.
(a white lie is a minor or harmless lie)
'while it circulates before start of election' is the wordplay.
'circulates' is an anagram indicator.
'before' is a charade indicator (letters next to each other).
'start of' suggests taking the first letters.
The first letter of 'election' is 'e'.
'while'+'it'='whileit'
'whileit' is an anagram of 'whiteli'.
'whiteli'+'e'='WHITE LIE'
(Other definitions for white lie that I've seen before include "Minor untruth, a pale fib" , "Minor falsehood" , "pardonable offence" , "Harmless untruth" , "Something untrue, but forgivable" .)