From para'; the hair (as dishevelled) -- locks.
see HEBREW para'
H6545. pera
I. מֶּ֫רַע noun [masculine] leader (?); — plural absolute מְּרָעוֺת בִּפְרֹעַ Judges 5:2 for the leading of the leaders (ᵐ5A Be Bu and others, but uncertain; ᵐ5B Symm, compare WeIsrael u. Jüd. Geschichte. (2), 97; Held.(2). 123 and elsewhere, for the loosing of locks [II. מֶּרַע], in vow of war; on these and other views see especially GFMon the passage; conjectures also by LambertRÉJ xxiv. 140 GrimmeZMG 1(1896), 572 CheJQ July 1899, 561 [reading ברכו]); construct אוֺיֵב מַּרְעוֺת מֵראֹשׁ Deuteronomy 32:42 from the head of leaders of the foe ᵐ5 Di Steuern and others; Kn Ke Dr and others from the long-haired heads of the foe.
II. מֶּ֫רַע noun [masculine] long hair of head, locks; — ׳פ absolute Ezekiel 44:20; construct ׳פ ראֹשׁוֺ שְׂעַר Numbers 6:5 (P). — Judges 5:2; Deuteronomy 32:42, see I.מֶּרַע above