Sentence:  Notwithſtanding certaine it is, that if thoſe Schoole men to their great thirſt of truth, and <WSD>vnwearied</WSD> trauaile of wit, had ioyned varietie and vniuerſalitie of reading and contemplation, they had prooued excellent Lights, to the great aduancement of all learning and knowledge: but as they are, they are great vndertakers indeed, and fierce with darke keeping. 
Meaning of the word marked with <WSD> tags:  Never tiring; tireless.