Frank is cold when he’s out (7)
I believe the answer is:
artless
'frank' is the definition.
(artless can mean frank or candid)
'cold when he's out' is the wordplay.
'cold when' becomes 'les' (I can't explain this - if you can you should believe this answer much more).
'he's' becomes 'Arts'.
'out' is an insertion indicator.
'les' placed inside 'arts' is 'ARTLESS'.
'is' is the link.
Can you help me to learn more?
(Other definitions for artless that I've seen before include "Plain" , "Natural like slaters" , "Without guile or sophistry" , "as an empty gallery" , "Simple, unaffected" .)