Crossword Genius

Posh replacement for that woman's aboard racehorse for business mogul (5)

Ross

I believe the answer is:

sugar

I'm a little stuck... Click here to teach me more about this clue!

This might be a double definition.

'posh replacement' is the first definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.

'for that woman's aboard racehorse for business mogul' is the second definition.
The definition suggests a singular noun which matches the answer.

Can you help me to learn more?

(Other definitions for sugar that I've seen before include "Sweeten" , "Mild oath (granulated?)" , "Sucrose" , "Sweet ingredient" , "White crystalline sweetener" .)

I've seen this clue in The Telegraph.
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