1) Broke 2) Broke a bronco 3) Broke, on a ranch 4) Broken 5) Broken in 6) Broken to harness 7) Broken, on a ranch 8) Brought from wildness 9) Brought into line 10) Brought under control 11) Busted a bronco 12) Caused to submit 13) Cultivated 14) Docile 15) Docile, now 16) Domestic 17) Domesticated 18) Emulated a horse whisperer Found on https://www.crosswordclues.com/clue/tamed