I know it's in the poem "Richard Cory" by Edwin Arlington Robinson. I was wondering myself what it meant and hoped this question would already have been answered but I guess it hasn't; so here's my answer: He glittered (meaning brilliant or showy; superficial attractiveness) when he walked because he wanted to present to his fellow citizens the image that he was who they thought he was, but he wasn't. Apparently, he was rich of course like everyone thought, and he did walk around appearing to be the happiest man in the world, but he had some issues going on. The guy shot himself for Christ's sake!
To repeatedly add glitter to something already well glittered
Her eyes glittered in the moonlight.She loved the way the stars glittered in the night sky.
While the night was could the stars glittered overhead.
of Glitter
Not everything that glitters is Gold. His eyes glittered with greed. The water glittered in the sunlight.
glittered
sparkled :D
The cast of The Gold That Glittered - 1917 includes: Frank Brule Mildred Manning Albert Roccardi
glowed burned
dejection
Climbing up the canyon, the Colorado River glittered in the sun far below us.
This dream seems to express a positive, optimistic attitude that perceives happiness on the horizon.