Unconditioned Punishment refers to a stimulus change that inherently decreases the likelihood of a behavior in the future without needing any prior learning or pairing with other forms of punishment. These punishers are naturally aversive and do not require conditioning to have their effect.
Example
Touching a hot stove and immediately experiencing pain is an example of unconditioned punishment. The painful stimulus naturally decreases the likelihood that the person will touch the hot stove again, without the need for prior learning or pairing with other punishers.