Toughness shown by engineers, source of industry amid quiet (10)
I believe the answer is:
resilience
'toughness' is the definition.
'engineers source of industry amid quiet' is the wordplay.
I cannot really understand how this works, but
'engineers' could be 'res' and 'res' is found within the answer.
This explanation may well be incorrect...
'shown by' acts as a link.
Can you help me to learn more?
(Other definitions for resilience that I've seen before include "Ability to bounce back" , "Ability to recover quickly" , "flexibility" , "Ability to spring back" , "make quick recovery" .)