Actor chooses to conceal lamp (5)
I believe the answer is:
torch
'lamp' is the definition.
(I know that torch is a type of electric lamp)
'actor chooses to conceal' is the wordplay.
'to conceal' says the answer is hidden in the clue.
'TORCH' is hidden within 'actor chooses'.
(Other definitions for torch that I've seen before include "Small hand-held battery lamp" , "Set fire to - hand-held light" , "Flashlight" , "Light carried in the hand" , "Link" .)