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