Groom's job? Running after bride at the start (8)

I believe the answer is:

brushing

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'groom's job?' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?

'running after bride at the start' is the wordplay.
'running' becomes 'rushing' (rushing is a kind of running).
'after bride' becomes 'b' (I am not sure about this - if you are sure you should believe this answer much more).
'at the start' means one lot of letters go next to another.
'rushing' after 'b' is 'BRUSHING'.

Can you help me to learn more?

I've seen this clue in The Guardian.

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