Friendly or dreadfully cold air (7)
I believe the answer is:
cordial
'friendly' is the definition.
('cordial' can be similar in meaning to 'friendly')
'dreadfully cold air' is the wordplay.
'dreadfully' indicates anagramming the letters.
'cold'+'air'='coldair'
'coldair' with letters rearranged gives 'CORDIAL'.
'or' is the link.
(Other definitions for cordial that I've seen before include "Warm and friendly; drink" , "drink with a fruity flavour" , "7 [HEARTY]" , "Warmly welcoming to the drink" , "Hearty, affectionate" .)