Acumen
/əˈkjuː.mən/ noun mediumThe ability to make fast, accurate judgments and decisions in a particular field.
Her sharp business acumen allowed her to spot a profitable opportunity that every other investor had overlooked.
Memory Trick
The word contains 'acu-,' as in 'acute' or 'acupuncture' — sharp acumen is a mind that pierces straight to the right answer like a fine needle.