Unruly engineers start to rant in workshop (10)
I believe the answer is:
refractory
'unruly' is the definition.
(I've seen this before)
'engineers start to rant in workshop' is the wordplay.
'engineers' becomes 're' (Royal Engineers).
'start to' indicates taking the first letters.
'in' is an insertion indicator.
'workshop' becomes 'factory' (I can't justify this - if you can you should give a lot more credence to this answer).
The initial letter of 'rant' is 'r'.
'r' inserted inside 'factory' is 'fractory'.
're'+'fractory'='REFRACTORY'
Can you help me to learn more?
(Other definitions for refractory that I've seen before include "Difficult to control" , "recalcitrant" , "Stubborn, unruly" , "Disobedient - uncontrollable" , "Obstinate, wilful" .)