Slovenly hotel dejected chums are upset over (8)
I believe the answer is:
slapdash
'slovenly' is the definition.
(thesaurus)
'hotel dejected chums are upset over' is the wordplay.
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'dejected' becomes 'sad' (associated in meaning).
'chums' becomes 'pals' ('pal' can be a synonym of 'chum').
'are upset over' says the letters should be written in reverse.
'h'+'sad'+'pals'='hsadpals'
'hsadpals' backwards is 'SLAPDASH'.
(Other definitions for slapdash that I've seen before include "Quick, careless" , "Hastily and carelessly done" , "Slipshod, sloppy" , "Blow followed by sprint - that's careless" , "recklessly" .)