Not in working order, unable to function. For example, The drawbridge is out of commission so we'll have to take the tunnel. This idiom originally referred to a ship that was laid up for repairs or held in reserve. Similarly, the antonym,
in commission, referred to a ship armed and ready for action. The latter term is also used in more general contexts today, as in My car's back in commission now, so we can drive to the theater.
[ Late 1800s