Guard present in a cinema (6)
I believe the answer is:
screen
This clue could be a double definition.
'guard present' is the first definition.
'screen' can be an answer for 'guard' (screen can mean to guard or protect). I'm not sure about the 'present' bit.
'cinema' is the second definition.
(I've seen this before)
'in a' is the link.
Can you help me to learn more?
(Other definitions for screen that I've seen before include "Movable partitions" , "Investigate (someone) for suitability; conceal" , "Examine for suitability, sift" , "Cover - cinema" , "Show pictures on the surface" .)