Adjoin rhymes with:
conjoin, enjoin, join, rejoin, ardoin, aucoin, beaudoin, boudoin, bourgoin, bowdoin, boyne, broin, burgoyne, chaudoin, chicoine, coin, conjoin, coyne, des_moines, enjoin, goin, goyne, groin, hoyne, jodoin, join, lemoine, leoine, loin, mccoin, mcgloin, micoin, purloin, raboin, rejoin
Adjoin sounds like:
addison, adhesion, adjani, adkison, adkisson, aitchison, aitken, atcheson, atchison, atheism, atkin, atkison, atkisson, attkisson, autism