tickler

Short definition from Wiktionary

Noun

1. 1
   One who tickles.
2. 2
   A person who or thing which amuses or excites.
3. 3
   A reminder.
4. 4
   A latex condom that has additional protrusions, for enhancing the sexual pleasure of the user.
5. 5
   Something puzzling or difficult; a conundrum.
6. 6
   A tickler file, file cabinet, or similar containing memoranda of deadlines arranged in date order.
7. 7
   A prong used by coopers to extract bungs from casks.
8. 8
   A dram of spirits.
9. 9
   Something puzzling; a poser.
10. 10
    A small notebook that fits the pocket or pocket notebook.