Not able to assume active duty.
Not effective.
A member of the military who is unable to assume active duty.
Lacking recent experience, out of practice, especially with respect to a skill or activity.
Affected with the fungal plant disease called rust.
Marked or corroded by rust.
Of clothing, especially dark clothing: worn, shabby.
Discolored and rancid; reasty.
Of the rust color, reddish or reddish-brown.
A gun or in particular an old or worn one.