Think you can write one? Have a go! (5)
I believe the answer is:
essay
'have a go' is the definition.
(thesaurus)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for essay that I've seen before include "Have a shot at a written piece" , "Attempt, try" , "Endeavour" , "example of Hazlitt's work" , "Attempt; written piece" .)