Blemished hotel covered by awful red stain (9)
'blemished' is the definition.
('tarnished' can be similar in meaning to 'blemished')
'hotel covered by awful red stain' is the wordplay.
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'covered by' is an insertion indicator.
'awful' indicates anagramming the letters.
'redstain' is an anagram of 'tarnised'.
'h' inserted inside 'tarnised' is 'TARNISHED'.
(Other definitions for tarnished that I've seen before include "Sullied", "Stained", "Having lost lustre", "Dulled, discoloured", "Blemished".)