Sentence:  ... he his guide requested / (For so from such as nearer stood we heard), / As over-tired, to let him lean awhile / With both his arms on those two massy pillars, / That to the arched roof gave main support. / He <WSD>unsuspicious</WSD> led him; ... 
Meaning of the word marked with <WSD> tags:  Not suspicious; not suspecting, unaware ("of" something).