Hit and run was achieved so carelessly (8)
I believe the answer is:
slapdash
'carelessly' is the definition.
(I've seen this before)
'hit and run' is the wordplay.
'hit' becomes 'slap' (both can mean to strike).
'and' is a charade indicator (letters next to each other).
'run' becomes 'dash' (dashing is a kind of running).
'slap'+'dash'='SLAPDASH'
'was achieved so' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for slapdash that I've seen before include "Carelessly hurried" , "Blow followed by sprint - that's careless" , "Quick, careless" , "Perfunctory" , "recklessly" .)