Charles Ellicott Commentary 2 Samuel 5:20

"And David came to Baal-perazim, and David smote them there; and he said, Jehovah hath broken mine enemies before me, like the breach of waters. Therefore he called the name of that place Baal-perazim." — 2 Samuel 5:20 (ASV)

Baal – perazim = possessor (or lord) of breaches. After David had inquired of the Lord and received a favourable answer (2 Samuel 5:19), he made a sudden attack, like a bursting forth of waters, and carried all before him. The victory was so signal as to give a new name to the locality, and to be remembered centuries afterwards as a memorable instance of Divine aid (Isaiah 28:21). The name has no reference to the heathen deity Baal.