Leave ship when monarch boards? Outrageous (5)

I believe the answer is:

gross

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'outrageous' is the definition.
(thesaurus)

'leave ship when monarch boards?' is the wordplay.
'leave' becomes 'go' (to go is to depart or leave).
'ship when' becomes 'ss' (prefix in ship names eg SS Great Britain. I am not sure about the 'when' bit.).
'monarch' becomes 'R' (abbreviation for regina, e.g. in ER ).
'boards?' means one lot of letters goes inside another.
'go'+'ss'='goss'
'goss' placed around 'r' is 'GROSS'.

Can you help me to learn more?

(Other definitions for gross that I've seen before include "Unattractively large; vulgar" , "Horribly fat" , "figure well over a ton" , "domestic product may be?" , "Product of 12s" .)

I've seen this clue in The Independent.

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