It is from Crash Course Media Literacy. It is at 4 minute and 52 second. Here is the context:
Suddenly, anyone, even an unlikely street kid without two pennies to rub together, could be in the know and feel like they were the king of the world.
I am aware of what the adjective means, but I cannot get what it means there. Dictionaries say that improbable is a synonim to unlikely. How could a kid be unlikely or improbable?
In that adjectival usage, unlikely means "one we would not expect" or "one who would not typically come to mind in this context".
Basketball player Dennis Rodman, an unlikely ambassador, met with the North Korean dictator.
It's linking unlikely to being in the know and feeling like they were the king of the world.
The street kid without two pennies to rub together would otherwise be unlikely to be and feel those ways except that [whatever happened suddenly] happened, and so now the kid does.
It's similar to the common phrase a likely story, meaning an excuse that happens to conveniently, exactly apply to a situation which would otherwise have consequences for the person telling the story:
A: How did you come into possession of all of those electronics?
B: I was just walking along the street and then saw them fall off of the back of a passing truck.
A: A likely story. [indicating that A does not believe that what B said is true]
