Pale-looking adult enters run-down cinema (7)
I believe the answer is:
anaemic
'pale' is the definition.
(I've seen this before)
'looking adult enters run-down cinema' is the wordplay.
'looking adult' becomes 'a' (abbreviation. I am not sure about the 'looking' bit.).
'enters' means one lot of letters goes inside another.
'run-down' is an anagram indicator (a run-down or ruined version of the letters).
'cinema' with letters rearranged gives 'naemic'.
'a' put within 'naemic' is 'ANAEMIC'.
Can you help me to learn more?
(Other definitions for anaemic that I've seen before include "Pale, sickly" , "Pale, weak in colour" , "Lacking in colour/vitality" , "Pallid, lacking vigour or colour" , "Member of a pride" .)