Small soft cry (4)
I believe the answer is:
weep
'cry' is the definition.
(I know that cry can be written as weep)
'small soft' is the wordplay.
'small' becomes 'wee' (Scottish term for small).
'soft' becomes 'p' (musical abbreviation for piano, 'soft').
'wee'+'p'='WEEP'
(Other definitions for weep that I've seen before include "Sob - ooze" , "Show emotion" , "leak" , "Bawl" , "Cry, shed tears" .)