כִּֽי־יִהְיֶ֣ה לְאִ֗ישׁ בֵּ֚ן סוֹרֵ֣ר וּמוֹרֶ֔ה אֵינֶ֣נּוּ שֹׁמֵ֔עַ בְּק֥וֹל אָבִ֖יו וּבְק֣וֹל אִמּ֑וֹ וְיסְּר֣וּ אֹת֔וֹ וְלֹ֥א יִשְׁמַ֖ע אֲלֵיהֶֽם׃
Jeżeliby miał kto syna rozpustnego i krnąbrnego, któryby nie słuchał głosu ojca swego, i głosu matki swojej, a karcili go, ale nie słucha ich;
Tze'enah Ure'enah
“A wayward and defiant son” [21:18]. The Torah wrote that when a son steals from his father and buys meat and wine, his father and mother bring him before the court, and the court allows him to be stoned. With this, a fear was created over all of Israel. They called out that a wayward and defiant son had been stoned, and therefore everyone feared to do evil.5Rashi, Deuteronomy, 21:18, 21.
Rashi
סורר (from the root סור to deviate) means, one who deviates from the proper path of life.
Chizkuni
כי יהיה לאיש וגו, “if a man has, etc.” the reason why the paragraph dealing with a wayward son is appended here is that if such a son is a firstborn, his rights as such are null and void, and the parent must deliver him to the court in order that he will be executed, i.e. he will inherit nothing, not only no double portion.