graywacke

aback, ack-ack, alack, amtrac, Anzac, arrack, attack, backpack, backtrack, Balzac, bareback, blackjack, blowback, bootblack, bootjack, brushback, bushwhack, buyback, callback, calpac, carjack, champac, cheapjack, coatrack, come back, comeback, cookshack, crackback, crookback, cut back, cutback, Dayak, dieback, Dirac, draw back, drawback, fall back, fallback, fastback, fast-track, fatback, feedback, finback, fireback, flapjack, flashback, fullback, gimcrack, giveback, greenback, gripsack, guaiac, halfback, half-track, hardback, hardhack, hardtack, hatchback, hayrack, haystack, hijack, hogback, hold back, holdback, hopsack, horseback, humpback, hunchback, Iraq, jam-pack, jet-black, Kanak, Karnak, kayak, Kazak, kickback, knapsack, knickknack, kulak, kyack, laid-back, lampblack, leaseback, linac, macaque, man jack, manpack, Micmac, mossback, muntjac, Muzak, notchback, offtrack, one-track, outback, packsack, payback, pitch-black, play back, playback, plow back, plowback, Prozac, pullback, quillback, racetrack, ransack, rickrack, roll back, rollback, roorback, rucksack, runback, sad sack, scatback, serac, set back, setback, shellac, shellback, shoeblack, shoepac, sidetrack, six-pack, skewback, skipjack, skyjack, slapjack, slotback, Slovak, smokejack, smokestack, snap back, snapback, snowpack, softback, sumac, swayback, sweepback, swept-back, switchback, tailback, tarmac, thornback, throw back, throwback, thumbtack, ticktack, tieback, tie tack, tombac, touchback, tow sack, trictrac, tripack, unpack, wetback, whaleback, wingback, wisecrack, wolf pack, woolpack, woolsack, yashmak, zwieback