Sinister rhymes with:
banister, cannister, chronister, alister, allister, armbrister, ballester, banister, barrister, burmester, callister, cannister, chedester, chidester, chronister, collister, edmister, flemister, forister, hardister, hiester, hollister, keister, kiester, macallister, regester, register, reister, riester
Sinister sounds like:
sanctuary, sangster, seamster, semester, sunstar