12 across
…
commanding
officer
essentially
use
the
truncheon
(4)
… commanding officer essentially use the truncheon (4)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
The definition is truncheon, meaning a cosh or bludgeon. The wordplay takes CO (commanding officer) plus the central letters of "use" and "the" (essentially) giving S and H, spelling COSH.