Attacks insect aboard ship (6)
I believe the answer is:
smites
'attacks' is the definition.
Although both the answer and definition are verbs in their -s form, I cannot understand how they can define each other.
'insect aboard ship' is the wordplay.
'insect' becomes 'mite' (I can't justify this - if you can you should give a lot more credence to this answer).
'aboard' is an insertion indicator.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'mite' going within 'ss' is 'SMITES'.
Can you help me to learn more?
(Other definitions for smites that I've seen before include "Deals a heavy blow" , "Strikes heavily or kills, biblical word" , "biblical hits" .)