Dirty shirt, short and tight (7)
I believe the answer is:
tarnish
'dirty' is the definition.
(thesaurus)
'shirt short and tight' is the wordplay.
'short' means to remove the last letter.
'tight' indicates an anagram (tight can mean drunk).
'and' with its last letter taken away is 'an'.
'shirt'+'an'='shirtan'
'shirtan' anagrammed gives 'TARNISH'.
(Other definitions for tarnish that I've seen before include "Stain or blemish, perhaps a reputation" , "Stain, metal or reputation" , "Cause to lose lustre, silver or reputation" , "Take the shine off" , "Lose lustre; sully" .)