Commentary for Genesis 26:21

שטנה old French nuisement; English hindrance.

ויחפרו...שטנה, from the word “Satan.” The name reflected the fact that every time they dug with success they would be subjected to this hatred.

ויקרא שמה שטנה, “he called its name Sitnah. (hatred, enmity) He had given the Philistines the benefit of the doubt regarding denying his claim to the first well his servants had dug. But now he knew that that had not been mere coincidence, but a display of their hatred of him.