Definition: Acumen; (Pronounced: uh-kyoo-muhn) Latin; noun
1. Quickness of perception or discernment (understanding)
Why I love this word:
Acumen is the ability to think clearly and make good decisions. You have a sense of keenness and depth of perception, discernment, or discrimination especially in practical matters. This word can also be used for self-improvement. You can discipline yourself to be cautious of not only the world around you but of the choices you are making. This word is also more commonly used in business as 'business acumen.' You would probably come across it in a job posting, or your boss will use it to encourage you to gain the ability to immediately excel beyond the standard of training.
Photograph from Live Journal