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