Devoutness shown in compassion about drug (5)
I believe the answer is:
piety
'devoutness' is the definition.
(I've seen this before)
'compassion about drug' is the wordplay.
'compassion' becomes 'pity' (pity is a kind of compassion).
'about' is an insertion indicator.
'drug' becomes 'e' (e is another name for ecstasy).
'pity' placed around 'e' is 'PIETY'.
'shown in' is the link.
(Other definitions for piety that I've seen before include "Reverent quality" , "Holiness" , "Reverence for a god" , "Spirituality" , "religious behaviour" .)