Heightening rhymes with:
brightening, enlightening, frightening, lightening, tightening, battening, brightening, captaining, disheartening, enlightening, fattening, flattening, frightening, heartening, lightening, shortening, smartening, straightening, sweetening, threatening, tightening
Heightening sounds like:
hastening, hastens, hasting, hastings, heightens, hesitancy, hesitating, hesitations, hesston's, hoisting, hostench, hosting, houghton's, houston's, hustings