Rant in public bath ultimately about Roger (3-5)

I believe the answer is:

tub-thump

'rant in public' is the definition.
(tub-thumping means expressing opinions in public)

'bath ultimately about roger' is the wordplay.
'bath' becomes 'tub' (synonyms).
'ultimately' says to take the final letters.
'roger' becomes 'hump' (both can mean to have sex).
The final letter of 'about' is 't'.
'tub'+'t'+'hump'='TUB-THUMP'

I've seen this clue in The Independent.

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