The adjective, cunning, has become more popular. Originally, the word meant crafty, deceitful, or evasive. Now, it also means attractive. The noun, cunning, draws upon the original adjective to mean achievement by deceit (a skill). Why was the original adjective pinned to a fox?
The noun, fox, describes a wild canine of small stature and distinctive features (pointy nose, bushy tail). Its color varies: Red, gray, tan, black, white, and usually its coat features a blend of two or more of those colors. People tend to remember the red coat. Interestingly, as the adjective, cunning, evolved to have a different meaning, the noun, fox, also evolved to mean attractive human female. In other words, If I said, “She is a fox,” most of you will know what I mean. The verb, fox, means deceive. That completes a circle. You can say, “The fox, foxed him,” and that would mean that the attractive woman deceived him.
A fox (the wild animal), being small in size, can be overpowered by a larger carnivore, such as a wolf. A fox can sprint for a short distance, but it can be outrun by a mountain lion. It cannot climb a tree. It can run down into an underground burrow, and it can dig, but its paws are not suitable to dig its way to escape danger. Probably, it does have to reason its way to safety and it does have to outwit its prey in order to eat. Personally, I have seen a rabbit outwit a fox. The rabbit doubled back onto its own trail, repeatedly, which confused the fox (it picked up its own scent mingled with the scent of the rabbit).
People use deceit (cunning) as a skill, mostly in competitive business practices. It tends to be people who perceive themselves to be disadvantaged that use it. They research their business environment to find key details and they keep those details secret as they plan how to use them to score a personal victory that achieves a company objective. This practice walks a line. The person who does this may be a hero for the day, and the company may truly benefit, but if the person does that repeatedly, he or she brands themself as a loner, a maverick (not a team player). Many marketers and salesmen use the tactic, get the win, then they move on to another job.
In the Christian Bible, you will find many passages that use the word cunning. The serpent (Satan disguised as a snake in the Garden of Eden) is described as being cunning, because it deceived Eve into believing that God’s word was untrue. God had told Adam and Eve not to eat fruit from “The Tree of Knowledge” or “You will die.” Satan, told Eve, “You will not surely die if you eat of it.” There is some debate, but I believe that “die” meant that the eater would set him or herself apart from God. It was the act of mankind (through Adam and Eve) of disobeying God that set all of us on a path away from God. Satan did worse by lying about what God said, thus he set himself on a path away from God (he had been beloved by God).
Web search Ezekiel 13:4 and Luke 13:32. The first passage is found in the Old Testament of the Bible, the time of prophets. The second passage is in the New Testament, a quote from Jesus, the Christ, about whom the prophets foretold. The passage was written by Luke, who accompanied the Apostle Paul on his missions to grow the Christian Church. In both passages, the fox appears to be deceitful.