Here's what rhymes with openun.
none nun naan one done run son sun won begun gun fun tion ton shun sion bun donne dun fon pun rien bn cen gon hun jun tonne tun ven yean anyone spun undone fron seisin stun toucan overrun outdone outrun overdone spline rerun redone misdone everyone twentyone cretonne Words that almost rhyme with openun
mum même num numb benumb some among become come young sum tongue hung lung cum dem sung thumb comme dumb gum rum dung hum rung wrung zum bum comm dum tum tung chum kung sm tem bung thrum yum from drum flung swung clung plum slum slung stung plumb scum crumb trom glum swum unsung sebum spume overcome sprung strung succumb overhung scrum strum rehung sacrum breadcrumb cerebrum frustum simulacrum candelabrum mullein mustn fustian puncheon