Bore with exercise (5)
I believe the answer is:
drill
I believe this is a double definition.
'bore' is the first definition.
(bore can mean to drill into something)
'exercise' is the second definition.
(military exercise)
'with' is the link.
(Other definitions for drill that I've seen before include "Stout cotton cloth" , "Seed machine; baboon" , "Exercise by repeated practice - bore" , "Dental assistant" , "strong twilled cotton" .)