Perhaps Morse caught over 500 people in the end (4)
I believe the answer is:
code
'perhaps morse' is the definition.
(I know that Morse code is a type of code)
'caught over 500 people in the end' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'over' becomes 'o' (cricket abbreviation).
'500' becomes 'D' (Roman numeral for 500).
'in the end' suggests the final letters.
The final letter of 'people' is 'e'.
'c'+'o'+'d'+'e'='CODE'
(Other definitions for code that I've seen before include "Secret symbols" , "System of rules" , "Secret system of letters. words etc" , "Program instruction" , "Established standards" .)