Family member that is entering new church (5)
I believe the answer is:
niece
'family member' is the definition.
(I've seen this before)
'that is entering new church' is the wordplay.
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'entering' indicates putting letters inside.
'new' becomes 'n'.
'church' becomes 'ce' (abbreviation for Church of England).
'n'+'ce'='nce'
'ie' placed into 'nce' is 'NIECE'.
(Other definitions for niece that I've seen before include "Criminal" , "[PRIEST'S] daughter?" , "Brother's daughter" , "One of the family" , "Family relation" .)