How many words are there which repeat a few letters twice in a row?

bookkeeper, hookkeeper possessionlessMississippi bathhouse, beachhead, fishhook, hitchhiker, roughhouse, withhold, genii, radii, skiing, taxiing,chukka, dekko, tikka, trekked, continuum, muumuu, duumvir, residuum, vacuum, bevvy, bivvy, civvies, chivvy, divvy, flivver, navvy, revving, skivvy, savvy, glowworm, meadowwort, strawworm, powwow