Overturn rhymes with:
downturn, minturn, taciturn, arterburn, bradburn, camburn, clayburn, cockburn, cogburn, downturn, eastburn, fairburn, fishburn, freeburn, glassburn, heartburn, kinburn, marshburn, mashburn, milburn, minturn, newburn, osburn, pangburn, redburn, redfern, sunburn, taciturn, washburn, washburne, winburn, woodburn
Overturn sounds like:
overdrawn, overthrown, overtrain