Podcast "Explicit Language"

If your podcast contains explicit language, you should check this box. This is particularly relevant in the U.S. and for English-language content.

The setting can also be applied at the episode level for individual episodes.

There is no exact definition of what explicit language really is, as it can be very subjective.
Apple Podcasts ( https://help.apple.com/itc/podcasts_connect/#/itcb54353390), the creator of the tag, provides guidelines for their Podcast RSS feed requirements.