Greenback's rhymes with:
greenbacks, greenbacks, greenbacks, greenbacks, buybacks, comebacks, cutbacks, drawbacks, flashbacks, fullbacks, givebacks, greenbacks, halfbacks, kickbacks, leasebacks, leatherbacks, paperbacks, paybacks, pricklebacks, pullbacks, quarterbacks, razorback's, razorbacks, rollbacks, setbacks
Greenback's sounds like:
greenback, greenbacks, greenbush, greenpeace, greenpeace's, grownups