Sentence:  In the old days, to my commonplace and unobserving mind, he gave no evidences of <WSD>genius</WSD> whatsoever. He never read me any of his manuscripts, [...], and therefore my lack of detection of his promise may in some degree be pardoned. 
Meaning of the word marked with <WSD> tags:  Someone possessing extraordinary intelligence or skill; especially somebody who has demonstrated this by a creative or original work in science, music, art etc.