Dingy is really an excellent word, really, because if anything makes you feel more drab and dusty and faded and generally as if you've slipped into one of the duller regions of the underworld then I don't know what it is.
There's a small English butterfly called a dingy skipper: I've always felt terribly sorry for it.
Mind you, I have to admit the poor thing really is quite dingy.
Word Not To Use Today: dingy. This word is probably related to the Old English word dynge, meaning dung.
Makes sense to me.