Sloppy make-up's run (8)
I believe the answer is:
slapdash
'sloppy' is the definition.
('slapdash' can be a synonym of 'sloppy')
'make-up's run' is the wordplay.
'make-up' becomes 'slap'.
'run' becomes 'dash' (dash is a kind of run**).
'slap'+'dash'='SLAPDASH'
(Other definitions for slapdash that I've seen before include "Perfunctory" , "Hastily and carelessly done" , "Messy" , "recklessly" , "Hasty and careless - hit and run?" .)