Only half aligns bins using this by way of a defence (5)
I believe the answer is:
alibi
'way of a defence' is the definition.
'alibi' can be an answer for 'defence' (defence given to police by a suspect). I'm not certain of the 'way of a' bit.
'only half aligns bins using this by' is the wordplay.
'only half' suggests halving the letters.
'bins using' becomes 'bi' (I can't justify this - if you can you should give a lot more credence to this answer).
'this by' is a charade indicator (letters next to each other).
'aligns' with half the letters taken is 'ali'.
'ali'+'bi'='ALIBI'
Can you help me to learn more?
(Other definitions for alibi that I've seen before include "Making excuse" , "A claim one was elsewhere when crime took place" , "Story confirming innocence" , "Excuse, defence" , "Defence in court" .)