Cinema in the red a long time (5)
I believe the answer is:
odeon
'cinema' is the definition.
(I've seen this before)
'in the red a long time' is the wordplay.
'in the red' becomes 'od' (overdrawn).
'a long time' becomes 'eon' (eon is a kind of long time).
'od'+'eon'='ODEON'
(Other definitions for odeon that I've seen before include "dramas here" , "Place for cinema or musical and dramatic performances" , "Greek music theatre" , "Ancient Greek building for music" , "old theatre" .)