Hi. If you're including "oy" in the word; "enjoy" is a five letter word that ends with "oy" enjoy
Ahoy
Ay, by, my, oy, Sy, Ty, Cy
Some words ending with OY are:ahoyalloyannoybatboybeachboybellboyboybuoybusboycloyconvoycorduroycowboycoydecoydeploydestroyemployenjoyenvoyhighboyhomeboyhouseboyjoykilljoylowboynewsboyoverjoypageboypaperboyplayboyploysavoyschoolboysoytallboytomboytoytroyviceroy
The word "futile" fits the criteria for a 9-letter word meaning useless with the vowel sound oi or oy.
loyal
appointment
envoy enjoy
olla Pronunciation: oy ya
Canada - end with a, holly - end with y, way - end with ay, hey _ end with ey, enjoy - end with oy,
By, my ----------------- AY, BY, MY, OY
No. The OY pair has the oi/oy diphthong sound, not the long E of a consonant-Y ending.