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