Have a striking idea that may come to nothing if NG (3,2)
I believe the answer is:
hit on
'have' is the definition.
Both the answer and definition are verbs in their base form.
Perhaps you can see a link between them that I can't see?
'a striking idea that may come to nothing if ng' is the wordplay.
I cannot really understand how this works, but
'striking' could be 'hit' (hit is a kind of striking) and 'hit' is present in the answer.
'nothing' could be 'o' (looks like zero - 0) and 'o' is located in the answer.
A single letter 'n' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for hit on that I've seen before include "Discover (something) by chance" , "Discovered suddenly or, in modern slang, made advances towards" , "Make advances to (US)" , "Discover; single out" , "Serendipitously find" .)