Pensilmaniac Share definition Flag Someone who thinks a lot and does nothing else, always zoned out, crying,laughing,and smiling to themselves Rebecca doesn’t talk to anybody and she’s always laughing to herself, I think she’s a pensilmaniac. Pensilmaniac by LilEdgySinBin January 13, 2020 0 0 Get merch Get the Pensilmaniac mug. Buy Now — $32.95 See more merch