Score eight tries, conversions harder originally (4)
I believe the answer is:
etch
'score' is the definition.
(etch can mean to score or carve into something)
'eight tries conversions harder originally' is the wordplay.
'originally' says to take the initial letters.
The initial letters of 'eight tries conversions harder' is 'ETCH'.
(Other definitions for etch that I've seen before include "Mark" , "Make incisions" , "Design on metal or glass using acid" , "Cut; engrave" , "Score with acid" .)