Meddling type engaged by organised unit (8)
I believe the answer is:
busybody
'meddling type' is the definition.
(I know this)
'engaged by organised unit' is the wordplay.
'engaged' becomes 'busy' (similar in meaning).
'by' says to put letters next to each other.
'organised unit' becomes 'body' (eg a government body).
'busy'+'body'='BUSYBODY'
(Other definitions for busybody that I've seen before include "Nosy parker" , "One minds everyone else's business" , "Nosey Parker" , "he'll nose around" , "Meddlesome type" .)