Here's what rhymes with dullify.
high thy vi hi shy sigh fi hy thigh vie psi hai cy fy sy thei phi by my why die lie y buy fly sky guy tie bi bye chi dye nigh pi pie spy thai dei fry ly quae rye sly ty wir alibi awry lye mai muy nai nullify pacify wry kai lai luy mei tai terrify wai mollify sty ossify stye lanai slier apply dry try cry justify occupy rely modify qualify alkali defy verify butterfly certify ply purify amplify pry ratify tri trie unify lullaby pri typify untie edify ramify aquae bonsai deify spry stultify amebae calcify horrify petrify turfy barfly mummify beatify banzais dandify yuppify supply reply thereby deny satisfy clarify hereby specify classify testify glorify gratify notify underlie diversify magnify rectify belie falsify pupae solidify termini amoebae codify crucify dignify liquefy overlie personify vilify acidify firefly retry stratify ultrahigh blowfly emulsify reunify liquify overfly scarify scurfy versify prettify shanghai vitrify ripply speechify overbuy syllabify identify imply nearby stimuli whereby comply multiply signify simplify goodbye alveoli fortify samurai standby beautify decry disqualify descry mortify resupply detoxify dragonfly mystify preoccupy triply vivify stupefy dissatisfy declassify hyperbolae drachmai gentrify solemnify nuclei intensify quantify indemnify objectify oversupply demystify electrify misapply revivify refortify exemplify reclassify cumuli transmogrify misidentify oversimplify