Still slowly going through the fours- here are the first ten that popped up that I either didn't know at all, or wasn't sure of:
PISO the Philippine peso (also POIS)
MUGG to make funny faces (knew MIGG, not this one)
UNDE wavy (an adjective, doesn't take an S- also DUNE, NUDE)
DORP a village (DROP, PROD. this one doesn't even look familiar)
BUTE a drug for treating arthritis (back hook of O, also TUBE)
SIDH a hill inhabited by supernatural beings in Irish folklore (sounds like an M. Night Shyamalan movie. takes an E, not an S, also DISH)
SKAT a card game (can't believe I didn't know KAT took a front S hook. also- KATS, TASK)
POME a fleshy fruit with a core (what, an abbreviation for pomegranate? ok. also, MOPE, POEM)
CYME a flower cluster (think I knew this but haven't seen it in a long time)
MONY many (adjective, no S)