A kadigan is a placeholder for an unspecified word. You know: blivet, deelie-bob, device, dingus, doodad, doohickey, doofunny, doover, fnord, gadget, geemie, gizmo, hoochamajigger, kerjigger, oojah, oojamaflip, thingamajig, thingamabob, thingamadoodle, thingo, thingum, thingummy, thingy, thing-thing, whatchamacallit, whatchamajigger, whatsit, whosey, whoseywhatsit, whosis, widget, whatsitsname.

These are common words that do useful work, but they have no formal part of speech, falling somewhere between nouns and pronouns. “Speak properly, and in as few words as you can, but always plainly,” wrote William Penn, “for the end of speech is not ostentation, but to be understood.”