Hung about to deter oil production (8)
I believe the answer is:
loitered
'hung about' is the definition.
The definition and answer can be both to do with fundamental existence as well as being past participle verbs.
Maybe you can see an association between them that I can't see?
'deter oil production' is the wordplay.
'production' indicates anagramming the letters.
'deter'+'oil'='deteroil'
'deteroil' is an anagram of 'LOITERED'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for loitered that I've seen before include "Hung around idly, dawdled" , "Hung about, with intent perhaps" , "Did tarry" , "Kicked heels" , "Stood about idly" .)