Defile

verb
make dirty or spotty, as by exposure to air; also used metaphorically
“The silver was tarnished by the long exposure to the air”
Similar: tarnish, stain, maculate, sully
noun
a narrow pass (especially one between mountains)
Similar: gorge
verb
place under suspicion or cast doubt upon
“sully someone's reputation”
Similar: sully, corrupt, taint, cloud
verb
spot, stain, or pollute
“The townspeople defiled the river by emptying raw sewage into it”
Similar: foul, befoul, maculate