The explanation of Word Detective is very funny but really not convincing.
The expression seems to be modelled after German Schneid and that has only a far relation with Schneider (tailor) as Schneid means something like courage, daring, efficiency.
Of a young daring officer one can say "Der hat Schneid",
and there is the expression " jemandem den Schneid abkaufen" meaning to be stronger than the daring opponent so that he loses his courage.
I have never had cause to look for the origin of Schneid. The origin may be Yiddish, but I strongly suspect that it is modelled after Latin acies. The basic meaning is sharpness as of the blade of a sword. Roman poets used acies metaphorically for
army, comparing the front line of the attacking legion to the sharpness of a sword.
The cutting edge of a sword is in German "die Schneide" and that I think is where metaphoric Schneid comes from.
So "Der hat Schneid " means he is like a sword the cutting edge of which is very sharp.
German Schneider is also an expression in connection with card games. If the opposing party has not even reached a certain limit of points they are Schneider, and have to pay the double sum to the winners. The origin of that expression seems to be a bit complicated. At least I don't have an explanation at hand. I don't want to exclude the possibility that Schneider (the term of card games) had an influence on the English expression, simply transferring a term of card games for a decisive victory over the opponent team to the sector of sports.
Now I have looked around a bit. Google has the American expression in the sports sector to get off the schneid (mostly spelled in this way). This corresponds to the German card games expression when a team has difficulty to reach 30 points. When at last they can reach 30 they are out off the Schneider. They have lost high but don't have to pay their loss with the double sum. (You win with 61 points in the card game Skat.)
So I have to correct my first view. The American expression has something to do with expressions of card games.