Silent parent (3)
I believe the answer is:
mum
I believe this is a double definition.
'silent' is the first definition.
(keep mum)
'parent' is the second definition.
(mum means a mother)
(Other definitions for mum that I've seen before include "Parent (who's kept or is the word!)" , "Mother - she's the word for secrecy" , "Parent - shtoom" , "Palindromic mater" , "old lady" .)