The empty traps show principles (6)
I believe the answer is:
tenets
'principles' is the definition.
(a tenet is a principle or belief)
'the empty traps' is the wordplay.
'empty' suggests removing the centre.
'traps' becomes 'nets' (net is a kind of trap).
'the' with its centre removed is 'te'.
'te'+'nets'='TENETS'
'show' is the link.
(Other definitions for tenets that I've seen before include "Doctrines of belief" , "Principles of belief" , "Doctrines or dogmas" , "Principles, beliefs" , "'Beliefs, dogmas (6)'" .)