Excessive noise worried uninitiated child at first (10)
I believe the answer is:
inordinate
'excessive' is the definition.
(synonyms)
'noise worried uninitiated child at first' is the wordplay.
'noise' becomes 'din' (din can mean a loud noise or disturbance).
'worried' becomes 'ate' (something worrying may eat someone up).
'uninitiated child' becomes 'inor' (I can't explain this - if you can you should give a lot more credence to this answer).
'at first' is a charade indicator (letters next to each other).
'din'+'ate'='dinate'
'dinate' after 'inor' is 'INORDINATE'.
Can you help me to learn more?
(Other definitions for inordinate that I've seen before include "Excessive" , "Unusually large" , "disorderly" .)