Disimprove

Definition of Disimprove
Dis`im`prove´
v. t. 1. To make worse; – the opposite of improve.
v. i. 1. To grow worse; to deteriorate.

Webster Dictionary

And here was me thinking my wife had made up this word because I never hear anyone else use that word. Sorry Jess. 🙂

What unusual words do the people in your life use?