For Louis I, a bad, bad feeling! (8)
I believe the answer is:
jealousy
'feeling' is the definition.
(jealousy is a kind of feeling)
'for louis i a bad bad' is the wordplay.
'for louis i' becomes 'je' ('I' in French - Louis is a common French name).
'bad bad' becomes 'lousy' (similar in meaning. I am not sure about the 'bad' bit.).
'je'+'a'+'lousy'='JEALOUSY'
Can you help me to learn more?
(Other definitions for jealousy that I've seen before include "Form of resentment" , "Suspicious resentment" , "Envious resentment" , "bad emotion" , "Feeling of envy" .)