Hotel employee showing quiet maturity (4)
I believe the answer is:
page
'hotel employee' is the definition.
(I've seen this in other clues)
'quiet maturity' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano').
'maturity' becomes 'age' (I've seen this before).
'p'+'age'='PAGE'
'showing' acts as a link.
(Other definitions for page that I've seen before include "Leaf of book etc" , "contact" , "contribution to book?" , "Court attendant" , "servant-boy" .)