Very bad style worn by Ron (7)
I believe the answer is:
chronic
'very bad' is the definition.
(I've seen this before)
'style worn by ron' is the wordplay.
'style' becomes 'chic' (chic can mean elegance or style).
'worn by' indicates putting letters inside (outside letters are worn by those on the inside).
'chic' enclosing 'ron' is 'CHRONIC'.
(Other definitions for chronic that I've seen before include "Awful" , "(Of illness) slow developing over a long time" , "(Of illness) lengthy; very bad (colloq.)" , "(Of disease) long-lasting" , "Of illness, prolonged or constantly recurring" .)