Amuse daughter going round water feature in capital (5)
I believe the answer is:
trevi
'water feature in capital' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'amuse daughter going round' is the wordplay.
'amuse' becomes 'divert' (synonyms).
'daughter' becomes 'd' (genealogical abbreviation).
'going' is a deletion indicator.
'round' says the letters should be written in reverse.
'divert' with 'd' removed is 'ivert'.
'ivert' written backwards gives 'TREVI'.
Can you help me to learn more?
(Other definitions for trevi that I've seen before include "flowing in Rome" , "Roman fountain" , "Rome fountain" .)