Wake-up call about mask and life on the outside (8)
I believe the answer is:
reveille
'wake-up call' is the definition.
(military wake-up call played on an instrument)
'about mask and life on the outside' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'mask' becomes 'veil' (I've seen this in another clue).
'and' means one lot of letters go next to another.
'life on the outside' becomes 'le' (I can't explain this - if you can you should believe this answer much more).
're'+'veil'+'le'='REVEILLE'
Can you help me to learn more?
(Other definitions for reveille that I've seen before include "Summons to get up" , "Army waking signal" , "The wake-up army bugle call" , "Signal to awaken soldiers at daybreak" , "Rousing bugle-call" .)