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