Lure in principle (6,4)
I believe the answer is:
ground rule
'principle' is the definition.
(I have seen 'Basic principle' mean 'ground rule' so perhaps 'principle' could also mean 'ground rule')
'lure' is the wordplay.
I cannot really see how this works, but
an anagram of 'lure' is 'rule' which is present in the answer.
The remaining letters 'ground' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for ground rule that I've seen before include "Basic principle" , "governs spectators' conduct at Lord's?" .)