Shortening rhymes with:
disheartening, heartening, smartening, battening, brightening, captaining, disheartening, enlightening, fattening, flattening, frightening, heartening, heightening, lightening, smartening, straightening, sweetening, threatening, tightening
Shortening sounds like:
sacredness, sardinas, sardines, sardonic, scrutinize, scrutinizes, scrutton's, secretions, sheraton's, shirting, shortens, shorting, shortness, shredding, shrewdness, shrouding, skirting, skywriting, sorting, squirting