Forgetful, disorganised (6)
I believe the answer is:
scatty
This clue is a double definition.
'forgetful' is the first definition.
(I've seen this before)
'disorganised' is the second definition.
(scatty means disorganised or absent-minded)
(Other definitions for scatty that I've seen before include "Slightly eccentric" , "Disorganised, unpredictable" , "Empty-headed" , "Slightly unpredictable" , "Forgetful and lacking focus" .)