Ring friend about Emilia's debut (4)
I believe the answer is:
peal
'ring' is the definition.
(synonyms)
'friend about emilia's debut' is the wordplay.
'friend' becomes 'pal' (pal is a kind of friend).
'about' means one lot of letters goes inside another.
'debut' indicates taking the first letters.
The initial letter of 'emilias' is 'e'.
'pal' enclosing 'e' is 'PEAL'.
(Other definitions for peal that I've seen before include "Deep prolonged sound" , "Carillon" , "Ring recurrently" , "Set of bells for ringing" , "Sound of bells, thunder" .)