wise > fashion
3 Or keep their cabins: much I am afeard,
keep > remain in afeard > afraid
4 Lest he like one of them himself disguise, 5 And turn his arrows to their exercise:
their exercise > (Either the nymphs' exercise, chasing game, or the arrows' usual exercise, so exciting love among the nymphs)
6 So may he long himself full easy hide:
full easy > very easily
7 For he is fair and fresh in face and guise,
guise > appearance
8 As any nymph (let not it be envied)."