Monsieur's ready with a kiss - potentially gross? (3-3)

I believe the answer is:

pre-tax

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'gross?' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'monsieur's ready with a kiss' is the wordplay.
'monsieur's ready' becomes 'preta' (I can't explain this - if you can you should believe this answer much more).
'with' says to put letters next to each other.
'a kiss' becomes 'x' (X can represent a kiss).
'preta'+'x'='PRE-TAX'

'potentially' acts as a link.

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