right > at once; very aware > watchful
3 To shun the engine of his meant decay;
engine > instrument meant decay > intended death
4 It booted not to think that throw to bear,
booted not to think > [did not bear thinking about: cf. 108.7:9] throw > throw; blow
5 But ground he gave, and lightly leapt arrear:
lightly > lightly; quickly arrear > backwards
6 Eft fierce returning, as a falcon fair,
Eft > Afterwards, then
7 That once has failed of her souse full near,