Insidious rhymes with:
fastidious, hideous, invidious, claudius, commodious, fastidious, hideous, invidious, melodious, odious, radius, studious, tedious, thaddeus
Insidious sounds like:
incata's, incestuous, incites, inequities, ingots, injects, injudicious, injustice, injustices, inkatha's, insect's, insects, insides, insights, insists, institute's, institutes, institutes'