Popular old pope, though harsh (9)
I believe the answer is:
inclement
'harsh' is the definition.
(I've seen this before)
'popular old pope' is the wordplay.
'popular' becomes 'in' ('in' can mean trendy).
'old pope' becomes 'Clement' (there have been several popes called Clement).
'in'+'clement'='INCLEMENT'
'though' is the link.
(Other definitions for inclement that I've seen before include "with heavens opening?" , "(Of weather) bad" , "not fair" , "Stormy" , "severe" .)