... being disorganised, she started backbiting (6)
I believe the answer is:
scatty
'being disorganised' is the definition.
(scatty means disorganised or absent-minded)
'she started backbiting' is the wordplay.
'started' suggests taking the first letters.
'backbiting' becomes 'catty' (I've seen this in another clue).
The initial letter of 'she' is 's'.
's'+'catty'='SCATTY'
(Other definitions for scatty that I've seen before include "dizzy" , "Feather-brained" , "Hare-brained" , "Mentally disorganised and absent-minded" , "Not thinking straight" .)