It's the verb/adjective sense, as in "I ran a marathon and am exhausted." rather than the noun sense, as in "The car's exhaust was unpleasant to breathe." In t

It's the verb/adjective sense, as in "I ran a marathon and am exhausted." rather than the noun sense, as in "The car's exhaust was unpleasant to breathe." In the sense used, "exhaust" means "to use up" or "to reach the limit" (in that you can go no further). The patent holder's patent rights are exhausted at sale, or the patent holder exhausts their patent rights at sale.