Damages are only required (in certain countries) for a legal case of slander to be successful, they're not needed to fulfil the definition of slander.
It would be slander if I said the words "HN user drw85 has never said a sentence that didn't contain racist abuse", even if my saying it has no impact on you or anyone at all.
(Just as it would be libellous - the equivalent of slanderous but for written rather than spoken lies about people - if I wrote a comment here on HN accusing you of being a mass murderer, even if you don't notice the comment and no law enforcement ever consider it of interest nor any other effects.)
'a false, spoken statement about someone which damages that person's reputation, or the making of such a statement'
I guess the distinction is important, because i could make a false statement that is not damaging, like 'swores has a red nose.', which might be a joke and thus is a false statement but not damaging nor slander.