Entrance alarm? (5,6)
I believe the answer is:
stage fright
'entrance alarm?' is the definition.
The answer and definition can be both feelings as well as being singular nouns.
Maybe there's a link between them I don't understand?
'entrance alarm?' is the wordplay.
'entrance' becomes 'stage' (I can't explain this - if you can you should give a lot more credence to this answer).
'alarm?' becomes 'fright' (both can mean fear or worry).
'stage'+'fright'='STAGE-FRIGHT'
Can you help me to learn more?
(Other definitions for stage fright that I've seen before include "attack of nerves" , "Panic experienced by performer" , "problem for players" , "Pre-performance nerves" , "Nerves in front of an audience" .)