Cast member after being told this? (5,1,3)
I believe the answer is:
break a leg
'being told this?' is the definition.
The definition suggests a singular noun but the answer is not.
'cast member' is the wordplay.
I cannot quite understand how this works, but
'member' could be 'leg' (member can mean a limb) and 'leg' is found within the answer.
This explanation may well be incorrect...
'after' is the link.
Can you help me to learn more?
(Other definitions for break a leg that I've seen before include "Actors' good luck" , "but not on the piste" , "Good luck wish offered to actor in bleak rage" , "leading to member being in cast?" , "Good luck in the theatre!" .)