Layperson has no son working in the theatre (6)
I believe the answer is:
player
'the theatre' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'layperson has no son working' is the wordplay.
'has no' indicates named letters should be taken away.
'working' indicates anagramming the letters.
'layperson' with 'son' taken out is 'layper'.
'layper' is an anagram of 'PLAYER'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for player that I've seen before include "Sports participant" , "Performer" , "one on the wing, perhaps?" , "One taking part in a game" , "powerful participant" .)