I add this as a skill, mainly because it is something often overlooked.
Thinking around a definition, it is about being able to see connections and relationships between things and/or people. Some use terms such as 'common sense' and 'street smarts', but it is more extensive than that.
There has been so much study on communication, and what we glean from non-spoken is far more than what we capture in the words. Intonations, body language, and dress are good examples regarding personal interaction. Seeing the moment and the enviroment for queues. Understanding what they mean, and how to weigh them, factoring in our inherent biases.
I also add to the definition an ability to transition time and look ahead and behind. Instinctively knowing what will transpire and what has, lends to a strong strategic player.