workword

work +‎ word, perhaps as a calque of Dutch werkwoord (“verb”).

workword (plural workwords)

1. (rare) The operative word, especially in a thought, phrase, or idea; keyword.
   • 1945, The Log, volume 40, page 35:

     In peace, as in war, speed will be the workword. The less time required to rig and properly operate heavy-duty cranes and cargo lifts, the more tonnage you can handle.

• keynote, catchword