Brief from foreign leader spreading fake news (6)
I believe the answer is:
flying
'brief' is the definition.
(eg in a 'flying visit', a short visit)
'foreign leader spreading fake news' is the wordplay.
'leader' indicates taking the first letters.
'spreading fake news' becomes 'lying' (lies are false bits of information).
The initial letter of 'foreign' is 'f'.
'f'+'lying'='FLYING'
'from' is the link.
(Other definitions for flying that I've seen before include "- Boat; - bomb; - fox" , "Taking to the air" , "Travelling by air" , "''Those magnificent men in their ... machines'' (film theme song)" , "Famous train once from King's Cross" .)