Don't move in this wintry weather! (6)
I believe the answer is:
freeze
I believe this is a double definition.
'don't move' is the first definition.
('freeze' is a command to stay still)
'wintry weather' is the second definition.
(thesaurus)
'in this' acts as a link.
(Other definitions for freeze that I've seen before include "Economic measure - go rigid - refrigerate" , "Become icy" , "period of cold weather" , "Stand still!" , "Change to ice" .)