Falsehood obscuring French leader's biography (4)
I believe the answer is:
life
'biography' is the definition.
(I've seen this before)
'falsehood obscuring french leader's' is the wordplay.
'falsehood' becomes 'lie' (lie is a kind of falsehood).
'obscuring' means one lot of letters goes inside another (I've seen this in other clues).
'leader' says to take the initial letters.
The first letter of 'french' is 'f'.
'lie' enclosing 'f' is 'LIFE'.
(Other definitions for life that I've seen before include "'While there's .... there's hope'" , "Birth to death" , "Existence - biography" , "The longest sentence" , "Maximum stretch?" .)