Here's what rhymes with cavail.
fail sale sail avail veil hail shale vale assail hale faille male scale mail pale tail tale jail nail rail frail gale whale bail stale wail bale curtail dale pail snail flail kale unveil wale wassail carrell trail email travail inhale quail exhale quale braille gunwale topsail foresail grail hightail detail prevail entail bewail derail mainsail countervail impale monorail taffrail bobtail lugsail fingernail pigtail pellmell hangnail ponytail martingale nonpareil swallowtail tattletale