Charles Ellicott Commentary Numbers 21:3

"And Jehovah hearkened to the voice of Israel, and delivered up the Canaanites; and they utterly destroyed them and their cities: and the name of the place was called Hormah." — Numbers 21:3 (ASV)

And they utterly destroyed them and their cities. —The meaning of the verb used here is to devote to destruction, and therefore to destroy utterly. It is not clear whether this destruction was carried out at once, or whether the fulfillment of the vow took place at a later period. (Judges 1:17.) If the attack of the Canaanites was made at the time of the final departure from Kadesh, the latter view must be maintained, as it can hardly be supposed that the cities could have been rebuilt and again destroyed in such a short interval.

And he called the name of the place Hormah. —Better, And the name of the place was called Hormah. The word Hormah — that is, a devoted thing —is cognate with the verb that occurs in this and the preceding verse, and which is rendered utterly destroy. The place is so called by anticipation in Numbers 14:45, and, as with other names (for example, Bethel and Jacob), the name was probably given anew to the place on a later occasion (Judges 1:17).