Aside from magical methods, and means that make sitting uncomfortable, one might hide weapons as other things.
-A sword cane.
-A necklace that doubles as a garrot.
-A razor brimmed hat.
-A hollowed-out holy book conceals a flask of poison; it's bookmark is a fine blade.
-A flexible scimitar disguised as a belt, or
-flexible daggers disguised as bracelets.
-A brooch or medal that doubles as a throwing star.
-Ornate rings that screw together into a blowgun, with darts that hang on earrings.
-Heavy rings as brass-knuckles, or a retractable punch dagger.
[edit] Also fake body parts!
-Peg legs can hold all sorts of stuff.
-A glass eye could be a hollow hidey-hole for a length of razor wire.
-Hollow teeth can contain poison, either to suicide if necessary, or to strike with a breath weapon.