Decimate rhymes with:
glucosamate, acclimate, amalgamate, automate, glucosamate, glutamate, overestimate, underestimate, acclimate, amalgamate, automate, breakmate, checkmate, classmate, dichromate, glucosamate, glutamate, inmate, multimate, overestimate, papermate, phonemate, playmate, primate, roommate, schoolmate, shipmate, shoemate, shumate, stalemate, teammate, underestimate, unimate
Decimate sounds like:
d'genetta, dachshund, decandia, decant, decent, dechant, decimated, deigned, desanti, desanto, descend, descended, descent, designate, designated, designed, desmet, desmith, desmond, dessent, detachment, diaconate, dicomed, dignity, disanti, disanto, discount, discounted, disjoint, disjointed, dismayed, disowned, disseminate, disseminated, dissent, dissented, dissonant, disunity, docent, document, documenta, documented, doesn't, doughnut, dushyanth