I do it wrongly, being a fool (5)
I believe the answer is:
idiot
'being a fool' is the definition.
(I've seen this before)
'i do it wrongly' is the wordplay.
'wrongly' indicates an anagram.
'do'+'it'='doit'
'doit' anagrammed gives 'diot'.
'i'+'diot'='IDIOT'
(Other definitions for idiot that I've seen before include "Dolt" , "nutter" , "Silly person or dimwit" , "Imbecile" , "Unwise person" .)