Not able to have wild fun with the thing (5)
I believe the answer is:
unfit
'not able' is the definition.
Both the answer and definition are adjectives. Perhaps they are linked in a way I don't understand?
'wild fun with the thing' is the wordplay.
'wild' indicates anagramming the letters.
'with' means one lot of letters go next to another.
'the thing' becomes 'it'.
'fun' with letters rearranged gives 'unf'.
'unf'+'it'='UNFIT'
'to have' acts as a link.
Can you help me to learn more?
(Other definitions for unfit that I've seen before include "Inappropriate" , "Ill-suited" , "Not healthy" , "Not in good shape physically" , "Unsuitable" .)