4 But added flame to his former fire, 5 That well-nigh melted his heart in raging ire;
That > [That; so that] well-nigh > very nearly
6 Neither thenceforth his approved skill (to ward,
approved > proven, tested
7 Or strike, or hurtle round in warlike gyre)
gyre > {A turning round, a whirling}
8 Remembered he, nor cared for his safeguard,
safeguard > protection, security
9 But rudely raged, and like a cruel tiger fared.
rudely > violently fared > acted