sharpie
n. countable B2 Upper Intermediate US //ˈʃɑɹpi// UK //ʃˈɑːpaɪ// sharpie
n. a person who is very smart, clever, or has a lot of street smarts. It is a casual way to describe someone who is good at thinking on their feet.
n. a person perceived as intelligent, shrewd, or possessing significant street wisdom.
He is a real sharpie when it comes to fixing cars.
The manager hired a sharpie who could negotiate better deals with suppliers than anyone else on the team.