Outside hotel, salesmen knocked back drink (8)
I believe the answer is:
spritzer
'drink' is the definition.
(I've seen this before)
'outside hotel salesmen knocked back' is the wordplay.
'outside' indicates putting letters inside.
'hotel' becomes 'ritz' (I've seen this before).
'salesmen' becomes 'reps' (I've seen this in other clues).
'knocked back' shows that the letters should be reversed in order.
'reps' in reverse letter order is 'sper'.
'ritz' placed within 'sper' is 'SPRITZER'.
(Other definitions for spritzer that I've seen before include "Wine/soda drink" , "Wine mixed with sparkling water" , "Fizzy drink" , "Wine and soda mixture" , "Drink made of wine and sparkling water" .)