Circus is cool but victorian circus is far cooler and a common theme in goth clothing. You could give it a slightly burlesque feel by wearing a corset-type top and a circle skirt with a netting petticoat underneath (btw circle skirts are really easy to make if you can cut and do a small amount of sewing , netting petticoats can easily be made by sewing bits of netting onto a slip). This coupled with knee-high boots, back-combed hair, elbow length gloves and lots of eyeliner would be pretty cool.
Or a bearded lady.
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