Training tool (5)
I believe the answer is:
drill
I believe this clue is a double definition.
'training' is the first definition.
(I know that drill is a type of training)
'tool' is the second definition.
(drill is a kind of tool)
(Other definitions for drill that I've seen before include "Routine" , "Stout cotton cloth" , "Rehearsal of the procedure to be followed in an emergency" , "Dental assistant" , "Instruct" .)