Cautionary rhymes with:
concessionary, confectionary, confectionery, counterrevolutionary, deflationary, dictionary, discretionary, disinflationary, evolutionary, expansionary, expeditionary, functionary, inflationary, missionary, noninflationary, probationary, reactionary, recessionary, revolutionary, stationary, stationery
Cautionary sounds like:
castner, cathmor, codner, costner, costumer, cotner, cotnoir, cudmore, customary, customer