Start to persuade amateur to take part in a game (4)
I believe the answer is:
play
'take part in a game' is the definition.
(I've seen this in another clue)
'start to persuade amateur' is the wordplay.
'start to' says to take the initial letters.
'amateur' becomes 'lay' (similar in meaning).
The initial letter of 'persuade' is 'p'.
'p'+'lay'='PLAY'
'to' acts as a link.
(Other definitions for play that I've seen before include "Make sport" , "Drama; engage in games" , "Theatre production" , "Theatrical production" , "Amuse oneself - drama" .)