Soldiers taken in by quiet nurse in fraud (9)
I believe the answer is:
pretender
'fraud' is the definition.
(synonyms)
'soldiers taken in by quiet nurse' is the wordplay.
'soldiers' becomes 're' (Royal Engineers).
'taken in by' is an insertion indicator.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'nurse' becomes 'tender' (a nurse tends to patients).
'p'+'tender'='ptender'
're' put within 'ptender' is 'PRETENDER'.
'in' is the link.
(Other definitions for pretender that I've seen before include "One claiming a title" , "Claimant to a throne, usually without just title" , "One who claims a title or position" , "fake" , "One acting" .)