Charles Ellicott Commentary Psalms 68:21

"But God will smite through the head of his enemies, The hairy scalp of such a one as goeth on still in his guiltiness." — Psalms 68:21 (ASV)

Hairy scalp. — Literally, crown, or top, or head of hair. The word is rendered “pate” in Psalms 7:16.

This is probably a portrait of some historical person hostile to Israel. Others take it as a type of pride and arrogance, comparing the use of the Greek verb κομαν.

The word “scalp,” properly shell (compare to “skull”), was a word in common use at the time of the translation of the English Bible—

“White beards have armed their thin and hairless scalps
Against your majesty.”

Shakespeare: Richard II.