bluster, brother, buckler, buffer, Butler, Butler's, butter, cluster, cluttered, color, colour, comer, cover, cupboard, custard, Cutler, cutter, drummer, duller, flutter, Glover, govern, gunner, gutter, hover, Hubbard, hundred, Hussars, jugglers, juster, lover, luster, lustre, mother, Muller, mustard, muster, mutter, other, plumber, rather, rougher, rubber, rudder, runner, rupture, Rutgers, shudder, shutter, smother, smugglers, Somers, southern, structure, stubborn, Stuttgart, subtler, suburb, succor, succour, sucker, suffer, summer, supper, tougher, Tucker, upper, upsurge, upward, usher, uttered, utters

another, another's, conductor, discolored, discoloured, discover, instructor, midsummer, recover, uncover

infrastructure, rediscovered, undiscovered