noun

• One who tickles.
• (informal) A person who or thing which amuses or excites.
• A reminder.
• A latex condom that has additional protrusions, for enhancing the sexual pleasure of the user.
• (informal, dated) Something puzzling or difficult; a conundrum.
• (US, business) A tickler file, file cabinet, or similar containing memoranda of deadlines arranged in date order.
• (UK, dated) A prong used by coopers to extract bungs from casks.
• (dated) A dram of spirits.
• (slang) Something puzzling; a poser.