Put in prison hulk for training (10)
I believe the answer is:
internship
'training' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'put in prison hulk' is the wordplay.
'put in prison' becomes 'intern' (I've seen this before).
'hulk' becomes 'ship' (I am not sure about this - if you are sure you should believe this answer much more).
'intern'+'ship'='INTERNSHIP'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for internship that I've seen before include "practical training programme" , "Trainee's spell" , "Work experience position" , "being a trainee?" .)