It means a shot at goal (3)
I believe the answer is:
try
This clue could be a double definition.
'it means a' is the first definition.
The definition suggests a singular noun which matches the answer.
'shot at goal' is the second definition.
'try' can be an answer for 'shot' (both can mean an attempt). I'm unsure of the 'at goal' bit.
Can you help me to learn more?
(Other definitions for try that I've seen before include "Make an attempt" , "Go" , "Attempt - hear (legally)" , "Judge" , "Examine" .)