Abridged books containing article by unknown amateurs (5)
I believe the answer is:
laity
'amateurs' is the definition.
(I've seen this before)
'abridged books containing article by unknown' is the wordplay.
'abridged books' becomes 'lit' (abbreviation for literature. I am not sure about the 'abridged' bit.).
'containing' means one lot of letters goes inside another.
'article' becomes 'a' (the indefinite article in English).
'by' means one lot of letters go next to another.
'unknown' becomes 'y' (algebra).
'lit' enclosing 'a' is 'lait'.
'lait'+'y'='LAITY'
Can you help me to learn more?
(Other definitions for laity that I've seen before include "Non-clergy" , "Those not in holy orders" , "Non-clerics" , "Lay people" , "The people, not the clergy" .)