Imaginative log quietly growing (12)
I believe the answer is:
enterprising
'imaginative' is the definition.
(thesaurus)
'log quietly growing' is the wordplay.
'log' becomes 'enter' (I've seen this before).
'quietly' becomes 'p' (p for piano and quiet).
'growing' becomes 'rising' (rising is a kind of growing).
'enter'+'p'+'rising'='ENTERPRISING'
(Other definitions for enterprising that I've seen before include "Adventurous, resourceful" , "daring" , "Showing initiative" , "Entrepreneurial" , "Full of initiative" .)