Astute is a word that 99% of people don’t know. Or if they know, they think it’s a bad thing. Like shrewd… it is a missing thing… It is not part of the vocabulary of the uneducated, unsophisticated, simple folks who live a pedestrian existence.
Words are great divider of people. If it is beyond you… if it is beyond your comprehension, you probably get found out by now knowing the word.
Now, with that said: astute is a person who can tell things apart, even similar things, with certainty, and ease.