Ship on move suddenly reverses (6)
I believe the answer is:
trader
'ship' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'on move suddenly reverses' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'move suddenly' becomes 'dart' (I've seen this before).
'reverses' says the letters should be written backwards.
're'+'dart'='redart'
'redart' in reverse letter order is 'TRADER'.
Can you help me to learn more?
(Other definitions for trader that I've seen before include "Dealer, monger" , "Retard (anag.)" , "Tarred the dealer badly" , "One selling" , "Dealer who buys and sells" .)