Sacred word in a set of books collected by male artist (6)
I believe the answer is:
mantra
'sacred word' is the definition.
(I've seen this before)
'a set of books collected by male artist' is the wordplay.
'a set of books' becomes 'ant'.
'collected by' says to put letters next to each other (I've seen this in other clues).
'male' becomes 'm' (common abbreviation).
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'ant' after 'm' is 'mant'.
'mant'+'ra'='MANTRA'
'in' acts as a link.
(Other definitions for mantra that I've seen before include "Several words repeated frequently" , "Words repeated as an aid to meditation" , "Watchword" , "Word or phrase repeated as aid to meditation" , "it's said to aid concentration" .)