Quietly greeting character from abroad (3)
I believe the answer is:
phi
'character from abroad' is the definition.
(letter of the Greek alphabet)
'quietly greeting' is the wordplay.
'quietly' becomes 'p' (musical symbol).
'greeting' becomes 'hi' (hi is a kind of greeting).
'p'+'hi'='PHI'
(Other definitions for phi that I've seen before include "Twenty First Greek letter, pronounced as f" , "Greek letter sounding F" , "classic character" , "Greek letter; hip (anag.)" , "Twenty-first letter of the Greek alphabet" .)