Here’s another one I just used that seemed like a good entry for today.  Besides, you know how much I like words that have unknown etymologies.

gumption (gump·tion): / GUHMP shuhn /
noun

(1) courage to act; spunk; guts
(2) initiative; resourcefulness; aggressiveness
(3) common sense; shrewdness

[Etymology unknown.]

Usage: [via] Complain to your brand if you have the gumption to do so.