Sentence:  ... [Satan] held on / His midnight search, where soonest he might finde / The Serpent: him fast sleeping soon he found / In Labyrinth of many a round self-rowld, / His head the midst, well stor'd with suttle wiles: / Not yet in horrid Shade or dismal Den, / Nor <WSD>nocent</WSD> yet, but on the grassie Herbe / Fearless unfeard he slept ... 
Meaning of the word marked with <WSD> tags:  Causing injury; harmful.