Soft refusal by a girl (5)
I believe the answer is:
piano
'soft' is the definition.
('piano' can be similar in meaning to 'soft')
'refusal by a girl' is the wordplay.
'refusal' becomes 'no'.
'by' says to put letters next to each other.
'a girl' becomes 'pia' (**).
'no' after 'pia' is 'PIANO'.
(Other definitions for piano that I've seen before include "key holder" , "In musical notation, this means softly" , "one of 6 [STEINWAYS]" , "Softly, musically speaking" , "Softly (mus.)" .)