If a caveman exposes his genitals to a cavewoman in modern times, what would be the likely offense?

The likely offense in this scenario is indecent exposure. This is defined as the deliberate exposure of one's genitals in a public place or in the presence of others where such exposure is likely to be seen. The act must be intentional and done for the purpose of sexual arousal or gratification, or for the purpose of shocking or alarming others.

In this case, the caveman's actions would likely fall under the definitions of indecent exposure, as he is intentionally exposing himself to another person. The context of modern times adds to the relevance of the offense since social norms and laws against such behavior are well established today.

Public lewdness, while similar, typically involves more than just exposing oneself; it can include engaging in lewd acts in public. Sexual assault involves non-consensual sexual contact or behavior, which is not established in the scenario. Engaging in a prohibited sexual act typically refers to specific acts that are legally defined as crimes, which do not directly apply to mere exposure. Thus, indecent exposure is the most fitting charge given the behavior described.