I apparently can't come up with themes lately, which is not necessarily a bad thing. Aiming for the satisfying-hard but not slog-hard kind of themeless with this one. Maybe some clues are slightly mean, but hopefully it's doable.
The maybe-mean clues that might need an explanation for some: HOTEL (Boardwalk as in the Monopoly property), MATH (group is a math term for basically any set with a "reasonable enough" operation, like all whole numbers - positive and negative - with addition)