Mother, being catholic, shows some spirit (4)
I believe the answer is:
marc
'some spirit' is the definition.
(I've seen this before)
'mother being catholic' is the wordplay.
'mother' becomes 'ma' (ma can mean mother).
'being catholic' becomes 'RC' (abbreviation for Roman Catholic).
'ma'+'rc'='MARC'
'shows' is the link.
(Other definitions for marc that I've seen before include "Brandy made from fruit-refuse" , "Strong liquor" , "Brandy distilled from grape residue" , "Cram (anag.)" , "Spirit" .)