Taciturn rhymes with:
downturn, minturn, overturn, arterburn, bradburn, camburn, clayburn, cockburn, cogburn, downturn, eastburn, fairburn, fishburn, freeburn, glassburn, heartburn, kinburn, marshburn, mashburn, milburn, minturn, newburn, osburn, overturn, pangburn, redburn, redfern, sunburn, washburn, washburne, winburn, woodburn
Taciturn sounds like:
taxidermy, testerman, texstyrene, textron, ticketron