New artillery parts for a wife / attorney (5,6)

'attorney' is the definition.
(trial lawyer is a kind of attorney)

'new artillery parts for a wife' is the wordplay.
I cannot really understand how this works, but
'a' is within the answer.
'wife' could be 'w' (abbreviation) and 'w' is located in the answer.
an anagram of 'artillery' is 'trillayer' which is present in the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?