irreversible

/ˌˈɪ(r)rəˌvʌrsəbəl/

/ɪrəˈvʌsɪbəl/

If you can't undo something, it's irreversible. Time is always irreversible, as is the damage done to your skin by too much sun, so be sure to wear sunblock!

While you see reverse inside of this word, you wouldn't use it to describe a car that can't go backwards. However, if the car was in an accident and cannot be fixed, you could say that the damage done to the car was pretty much irreversible, in other words the car is totaled.

Definitions of irreversible

1. adjective

   incapable of being reversed
   “irreversible momentum toward revolution”

   synonyms:

   permanent

   not capable of being reversed or returned to the original condition

   antonyms:

   reversible

   capable of reversing or being reversed

   correctable

   capable of being returned to the original condition; not necessarily permanent

   rechargeable

   capable of being recharged