Asparagus, say, could give one a stabbing pain (5)
I believe the answer is:
spear
'asparagus say' is the definition.
The answer and definition can be both to do with fundamental existence as well as being verbs in their base form.
Maybe there's a link between them I don't understand?
'one a stabbing pain' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'a' (a thing is one thing) and 'a' is present in the answer.
'a' could be 'per' (eg 'one a day' means 'one per day') and 'per' is found within the remaining letters.
A single letter 's' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
'could give' acts as a link.
Can you help me to learn more?
(Other definitions for spear that I've seen before include "Weapon; asparagus stem" , "Lance" , "Sharp weapon" , "Primitive weapon" , "Asparagus shoot" .)