Behold! Return of French engaging in pastime (4)
I believe the answer is:
ludo
'french engaging in pastime' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe there's a link between them I don't understand?
'behold return of' is the wordplay.
'behold return' becomes 'lud' (I can't justify this - if you can you should give a lot more credence to this answer).
'of' becomes 'o''.
'lud'+'o'='LUDO'
Can you help me to learn more?
(Other definitions for ludo that I've seen before include "Game (meaning 'I play' in Latin)" , "race for four tokens" , "Loud sort of board game with dice and counters" , "Traditional board game" , "Children's board game" .)