* Anachronism: This is the most common and accurate term. It literally means "out of time" and refers to anything that is placed in the wrong historical period.
* Misplaced: This is a more general term that can be used for anything that is out of place, including things that are anachronistic.
* Incongruous: This word emphasizes the sense of being strange or out of place.
* Absurdity: This word implies that the thing is not only out of place, but also ridiculous.
* Paradox: This term works if the item or concept creates a logical contradiction due to its placement in time.
The best word to use will depend on the specific context. For example, if you are talking about a caveman with a watch, "anachronism" would be the most appropriate term. However, if you are talking about a modern-day person who dresses like a caveman, "incongruous" or "absurdity" might be better choices.