Soldiers may find it boring (5)
I believe the answer is:
drill
'boring' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for drill that I've seen before include "Dental assistant" , "Put a hole in" , "strong twilled cotton" , "Tool; military training" , "Material - exercise" .)