Hare-brained plan going around Washington aborted at the start (6)
I believe the answer is:
madcap
'hare-brained' is the definition.
(I've seen this before)
'plan going around washington aborted at the start' is the wordplay.
'plan' becomes 'map' (I've seen this before**).
'going around' means one lot of letters goes inside another.
'washington' becomes 'dc' (Washington DC).
'at the start' indicates taking the first letters.
The first letter of 'aborted' is 'a'.
'dc'+'a'='dca'
'map' placed around 'dca' is 'MADCAP'.
(Other definitions for madcap that I've seen before include "Dare-devil" , "Amusingly crazy (person)" , "Wild fellow" , "Given to reckless behaviour" , "Hothead" .)