Cutters founder, overturned, with last two of five on board (6)
I believe the answer is:
knives
'cutters' is the definition.
(knife is a kind of cutter)
'founder overturned with last two of five on board' is the wordplay.
'founder' becomes 'sink' (sinking is a kind of foundering).
'overturned' shows that the letters should be reversed in order.
'with last two of five' becomes 've' (I can't justify this - if you can you should give a lot more credence to this answer).
'on board' means one lot of letters goes inside another (inserted letters are taken on board).
'sink' back-to-front is 'knis'.
'knis' going around 've' is 'KNIVES'.
Can you help me to learn more?
(Other definitions for knives that I've seen before include "Daggers" , "Weapons" , "Cutting instruments" , "Blades" , "Cutting tools" .)