Cooking, Delia suffered (5)
I believe the answer is:
ailed
'suffered' is the definition.
(ailing is a kind of suffering)
'cooking delia' is the wordplay.
'cooking' is an anagram indicator (cook can mean to falsify or distort).
'delia' is an anagram of 'AILED'.
(Other definitions for ailed that I've seen before include "Felt bad" , "Was ill" , "Became sick" , "was giving trouble" , "was on the blink?" .)