Superpower rhymes with:
overpower, underpower, empower, overpower, power, underpower, auer, bauer, bougher, bower, brauer, brougher, brower, clower, cower, dauer, devour, dour, empower, flour, flower, gauer, glower, gower, grauer, hauer, hour, how're, hower, kauer, klauer, knauer, lauer, mauer, nauer, our, overpower, power, rauer, sauer, schauer, scour, shower, sour, tauer, tower, trower, underpower