Avoid uttering farewell to father boarding ship (6)
I believe the answer is:
bypass
'avoid' is the definition.
(bypassing is a kind of avoiding)
'uttering farewell to father boarding ship' is the wordplay.
'uttering' shows a homophone (sound like) (I've seen 'uttered' mean this).
'farewell' becomes 'bye' (bye is a kind of farewell).
'to father' becomes 'pa' (pa can mean dad or father).
'boarding ship' becomes 'ss' (I can't explain this - if you can you should believe this answer much more).
'bye' sounds like 'by'.
'by'+'pa'+'ss'='BYPASS'
Can you help me to learn more?
(Other definitions for bypass that I've seen before include "Ignore" , "Round-about way" , "Secondary channel - kind of operation" , "not found in the high street" , "Skirt" .)