Rashi on Exodus 34:14/רש"י על שמות ל״ד:י״ד

1קנא שמו WHOSE NAME IS קנא — Who is zealous (מקנא) to exact punishment from the sinners and is not indulgent towards idolatry. This (the above) is always the meaning of the root קנא wherever it is used in connection with God. Consequently קנא שמו His name (His characteristic) is קַנָּא that of a zealot, implies: He maintains (insists upon) his superiority over other gods, and punishes His enemies (those who worship idols).