Enduring restricted times for lying outside (8)
I believe the answer is:
external
'lying outside' is the definition.
(I've seen this before)
'enduring restricted times' is the wordplay.
'enduring' becomes 'eternal'.
'restricted' is an insertion indicator.
'times' becomes 'x' (multiplication sign).
'eternal' going around 'x' is 'EXTERNAL'.
'for' acts as a link.
(Other definitions for external that I've seen before include "Relating to the outside" , "Belonging to the outside" , "Lying outside" , "abroad" , "Coming from outside" .)