Crossword Genius

Charge speechifying Liz's fella, commonly? (4)

Ross

I believe the answer is:

fill

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'charge' is the definition.
(I've seen this in other clues)

I don't understand how the remainder of the clue works.

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(Other definitions for fill that I've seen before include "Satisfy (a need)" , "Become satiated" , "Completely occupy" , "` `Work expands to .... the time available' '" , "Top up" .)

I've seen this clue in The Guardian.
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