Contented sound made by pig with light source attached to its tail (8)
I believe the answer is:
gruntled
'pig with light source attached to its tail' is the definition.
I can't tell whether this defines the answer.
'contented sound made by' is the wordplay.
'contented sound' becomes 'grunt' (I have seen 'Inarticulate sound ' mean 'grunt' so perhaps 'sound' could also mean 'grunt'. I am not sure about the 'contented' bit.).
'made' becomes 'led' (leading is a kind of making).
'by' says to put letters next to each other.
'grunt'+'led'='GRUNTLED'
Can you help me to learn more?
(Another definition for gruntled that I've seen is " Happy".)