Phoney source of fuel in Ireland, you said, is imported (5)
I believe the answer is:
bogus
'phoney' is the definition.
(synonyms)
'source of fuel in ireland you said is imported' is the wordplay.
'source of fuel in ireland' becomes 'bogs' (I am not sure about this - if you are sure you should believe this answer much more).
'you said' becomes 'U' (homophone of 'you').
'is imported' indicates putting letters inside.
'bogs' enclosing 'u' is 'BOGUS'.
Can you help me to learn more?
(Other definitions for bogus that I've seen before include "Fake, phoney" , "Spurious" , "Fake, sham" , "false impression" , "Fraudulent, fake" .)