Badly leaking connection (7)
I believe the answer is:
linkage
'connection' is the definition.
(I know that linkage is a type of connection)
'badly leaking' is the wordplay.
'badly' indicates anagramming the letters.
'leaking' with letters rearranged gives 'LINKAGE'.
(Other definitions for linkage that I've seen before include "System of connections" , "Part of mechanism" , "where the join is" , "Connection, coupling" , "Leaking (anag)" .)