Is 'aspersion' always untrue?

[Aspersionnn]

The word 'aspersion' is usually translated in English-Polish dictionaries as 'oszczerstwo', which means something definitely untrue and insulting.
Is it also in English? Or maybe it is just an unfavourable remark?
Greetings

[Casiopea]

It's a noun and it means, an attack on someone's character or reputation.

Welcome, Aspersionn.

[rewboss]

It's also very uncommon. I've only ever heard it in the phrase "casting aspersions", which is an idiom: "Are you casting aspersions on my efforts?" It's probably better to avoid using that word in other contexts.