Sentence:  When this <WSD>operose</WSD> and hard-working student descended from his closet, and gained a sort of tacit leave from his tutor to join in the circle of us gay and high-spirited fellows, the part he played was no more advantageous to him, than his former exhibition had been among the learned. 
Meaning of the word marked with <WSD> tags:  Of a person: busy, industrious, or painstaking.