People lose their head and run off to Gretna Green (5)
I believe the answer is:
elope
'people' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how they can define each other.
'lose their head and run off to gretna green' is the wordplay.
I cannot really see how this works, but
'run' could be 'lope' (lope is a kind of run) and 'lope' is located in the answer.
A single letter 'e' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for elope that I've seen before include "Run away to wed" , "Flee to wed" , "Run away with lover" , "Run away secretly to marry" , "Run off with Mr/Ms Right" .)