Nasty weather - wind (7)
I believe the answer is:
wreathe
'wind' is the definition.
('wreathe' can be a synonym of 'wind')
'nasty weather' is the wordplay.
'nasty' indicates an anagram.
'weather' with letters rearranged gives 'WREATHE'.
(Other definitions for wreathe that I've seen before include "Encircle with flowers" , "wind" , "Weather (anag.)" , "Twist together" , "Intertwine, curl round" .)