Pleasant having European relative (5)
I believe the answer is:
niece
'relative' is the definition.
(type of relative)
'pleasant having european' is the wordplay.
'pleasant' becomes 'nice' (associated in meaning).
'having' is an insertion indicator.
'european' becomes 'e' (abbreviation e.g. EU).
'nice' going around 'e' is 'NIECE'.
(Other definitions for niece that I've seen before include "One of the family" , "Daughter of a sibling" , "Young female relative" , "Brother's girl" , "Family girl" .)