STOP is today's theme, or "S to P." It's fine, I guess. I like STEELTRAP (56A: *Sharp mind, figuratively) and SKINNYDIP (20A: *Go swimming in one's birthday suit).
Nothing too outrageous today. Maybe ERL (9D: Schubert's "The ____ King"), but I'm pretty sure Colum will know that, so I can't complain too loudly. ALAE, ESAI, EPEE… the usual stuff.
LASHES (29A: Punishment for a mutineer) was colorful, and took a few crosses, WEAPON (45A: One-third of a Clue accusation) was fun, and could have been "person," I suppose. And ALFAROMEO (34D: Sports car with a Spider model) was unusual to see, although not at all difficult.
Best clue: 50D: Trash-talking Muppet? (OSCAR).