Returning to sea, arranged to get rid of (5)
I believe the answer is:
erase
'get rid of' is the definition.
(thesaurus)
'returning to sea arranged' is the wordplay.
'returning to' becomes 'er' (I can't explain this - if you can you should give a lot more credence to this answer).
'arranged' is an anagram indicator.
'sea' anagrammed gives 'ase'.
'er'+'ase'='ERASE'
'to' is the link.
Can you help me to learn more?
(Other definitions for erase that I've seen before include "Do away with" , "Remove all traces of" , "Rub out, expunge" , "Scratch" , "Rub out, cancel" .)