Tough soldiers not speaking about the final part of WWII (9)
I believe the answer is:
resilient
'tough' is the definition.
(I've seen this before)
'soldiers not speaking about the final part of wwii' is the wordplay.
'soldiers' becomes 're' (Royal Engineers).
'not speaking' becomes 'silent' (I've seen this in another clue).
'about' is an insertion indicator.
'the final part of' indicates one should take the final letters.
The final letter of 'wwii' is 'i'.
'silent' placed around 'i' is 'silient'.
're'+'silient'='RESILIENT'
(Other definitions for resilient that I've seen before include "Tough" , "Bouncy" , "Elastic" , "Irrepressible" , "Rebounding from impact" .)