Sillier rhymes with:
chillier, hillier, hillyer, hilyer, bollier, boulier, bouthillier, boutilier, brallier, caillier, callier, charlier, chillier, cochlear, colier, collyer, colyer, costlier, cuvelier, deadlier, earlier, friendlier, fuselier, gallier, hellyer, hillier, hillyer, hilyer, holier, hollier, jollier, lallier, langelier, letellier, likelier, livelier, mononuclear, montpelier, nuclear, parlier, sadlier, salyer, soulier, tellier, thermonuclear, tullier, uglier, vallier
Sillier sounds like:
sacilor, sackler, sailer, sailor, salary, saller, salyer, sayler, saylor, scalar, scalera, schaller, scheeler, scheler, scheller, schickler, schiller, schisler, schissler, schleyer, schoeller, scholar, scholer, scholler, schooler, schueler, schueller, schuessler, schuler, schuller, schussler, schuyler, schwalier, schwaller, schwegler, scolari, scolaro, sealer, sechler, seckler, secular, segler, seigler, seiler, seller, sellier, sesler, sessler, seyler, seyller, shaler, shallower, shawler, sheckler, sheeler, sheller, shelor, shiller, shisler, shissler, sholar, shular, shuler, sickler, siegler, sieler, sigler, siler, siller, sisler, sizeler, sizzler, sklar, skoler, slayer, slower, slur, slurry, solar, solari, soler, soleri, soller, solorio, soulier, soulliere, squalor, suhler, syler