Quiet Yankee, the retiring type (3)
I believe the answer is:
shy
'retiring type' is the definition.
'shy' can be an answer for 'retiring' (I've seen this in another clue). I am not sure about the 'type' bit.
'quiet yankee' is the wordplay.
'quiet' becomes 'sh' (both can be said to tell someone to be quiet).
'yankee' becomes 'Y' (phonetic alphabet: alpha, bravo, charlie etc.).
'sh'+'y'='SHY'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for shy that I've seen before include "Suddenly start" , "Timid and self-conscious" , "cast" , "Demure" , "Nervous or timid in company" .)