Let-off :: Let-off (n.) A device for letting off, releasing, or giving forth, as the warp from the cylinder of a loom..
Let-up :: Let-up (n.) Abatement; also, cessation; as, it blew a gale for three days without any let-up..
Violet-tip :: Violet-tip (n.) A very handsome American butterfly (Polygonia interrogationis). Its wings are mottled with various shades of red and brown and have violet tips.