Smart little Euphemia collects just over 100 books (9)
I believe the answer is:
efficient
'smart' is the definition.
'little euphemia collects just over 100 books' is the wordplay.
'little euphemia' becomes 'effie' (short for Euphemia. I am not sure about the 'little' bit.).
'collects' indicates putting letters inside.
'just over e00' becomes 'ci' (e0e in Roman numerals).
'books' becomes 'nt' (abbreviation for New Testament).
'effie' enclosing 'ci' is 'efficie'.
'efficie'+'nt'='EFFICIENT'
(Other definitions for efficient that I've seen before include "Effective in doing what is required" , "Functioning effectively" , "working economically at speed" , "Working in a well-organised and competent way" , "Not wasting energy" .)