Dupin's alter ego in Silk Road city ignoring a character (4)
I believe the answer is:
sand
'character' is the definition.
(I know that sand is a type of fortitude)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for sand that I've seen before include "George - - (French authoress)" , "Granular substance" , "Rub down (for painting)" , "Seaside castle-building material" , "Fine stone particles" .)