Recluse has some productive time reflecting when standing on head (7)
I believe the answer is:
eremite
'recluse' is the definition.
(I've seen this in another clue)
'some productive time reflecting when standing on head' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'when standing on head' shows that the letters should be reversed in order (in a down clue, letters go up).
'etimere' is hidden in the letters of 'productive time reflecting'.
'etimere' reversed gives 'EREMITE'.
'has' acts as a link.
(Other definitions for eremite that I've seen before include "Religious person" , "Christian hermit or recluse" , "Christian living in severe circumstances" , "Solitary" , "ascetic" .)