disengager

disengage +‎ -er

disengager (plural disengagers)

1. One who, or that which, disengages.
   • 1946 March and April, “Old Brighton Line Signal Box”, in Railway Magazine, page 111:

     Another feature of the working which Major Marindin criticised, was the absence of any separate up home and distant signals for Wivelsfield Station box, which merely controlled the junction signals by disengager apparatus.

• degreasing, gingerades