Across: 2.old, 5.crab, 6.ugly, 7.oaf, 8.page, 10.fate, 13.golf, 16.sack, 18.ump, 19.asks, 20.urge, 21.sod

Down: 1.area, 2.oboe, 3.duff, 4.flat, 8.peg, 9.gal, 11.ASA, 12.elk, 14.oust, 15.fuss, 16.spud, 17.cage