disdain > indignation, anger affronted > defied; confronted

3 Enforced her purple beast with all her might

Enforced > Encouraged; constrained

4 That stop out of the way to overthrow,

stop > obstacle [the squire]

5 Scorning the let of so unequal foe:

let > hindrance so > such [an]

6 But nathemore would that courageous swain

nathemore > never the more swain > youth, young man

7 To her yield passage, gainst his lord to go,