Go in quietly, getting up daring (12)
I believe the answer is:
enterprising
'daring' is the definition.
(I've seen this before)
'go in quietly getting up' is the wordplay.
'go in' becomes 'enter' ('enter' can be a synonym of 'go in').
'quietly' becomes 'p' (p for piano and quiet).
'getting up' becomes 'rising' ('rise' can be a synonym of 'get up').
'enter'+'p'+'rising'='ENTERPRISING'
(Other definitions for enterprising that I've seen before include "Adventurous, resourceful" , "Go ahead" , "Adventurous and imaginative" , "daring" , "Venturesome" .)