With sun out and warmth, he will take the cover off (9)
I believe the answer is:
unsheathe
'take the cover off' is the definition.
I can't judge whether this defines the answer.
'with sun out and warmth he' is the wordplay.
'with' means one lot of letters go next to another.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'and' means one lot of letters go next to another.
'warmth' becomes 'heat' (synonyms).
'sun' with letters rearranged gives 'uns'.
'uns'+'heat'='unsheat'
'unsheat' next to 'he' is 'UNSHEATHE'.
'will' acts as a link.
Can you help me to learn more?
(Other definitions for unsheathe that I've seen before include "Draw from a scabbard" , "Draw out (a knife)" , "Pull out (a blade)" , "Draw (weapon)" , "Remove from cover like sword" .)