Clot spoiled catalogue (9)
I believe the answer is:
coagulate
'clot' is the definition.
(I've seen this before)
'spoiled catalogue' is the wordplay.
'spoiled' indicates an anagram.
'catalogue' anagrammed gives 'COAGULATE'.
(Other definitions for coagulate that I've seen before include "Congeal" , "(Of blood) solidify" , "Thicken or clot, like blood" , "Set" , "Cause to clot" .)