Giving a signal to be lining up for hearing (6)
I believe the answer is:
cueing
'lining up for hearing' is the definition.
Although both the answer and definition are present participle verbs, I don't see how one could define the other.
'giving a signal to' is the wordplay.
'giving' means one lot of letters go next to another.
'a signal' becomes 'cue' (I've seen this before).
'to' becomes 'ing' (I can't explain this - if you can you should believe this answer much more).
'cue' next to 'ing' is 'CUEING'.
'be' acts as a link.
Can you help me to learn more?
(Other definitions for cueing that I've seen before include "Signalling actor to speak" , "Bringing in (an actor)" , "Prompting, actor perhaps" .)