discerner
/dɪsˈnɜrənər/Definitions
1. noun
A person with a keen sense of discernment, especially one who is skilled in distinguishing or judging between things.
“She was a skilled discerner of people’s true intentions.”
2. verb
To distinguish or judge between things, especially with keen discernment.
“The detective had to discern the difference between the suspect’s alibi and his actual whereabouts.”