"Ta slova nejsou dobrá."

Translation: The words are not good.

[GMadz7]

"Those are not good words" is incorrect?

[VladaFu]

Yes, that is "To nejsou dobrá slova.".

[EVAM20986]

The plural of a feminine noun remains the same?

[VladaFu]

I am not really sure what you mean. Slovo is a neuter word, the plural slova is neuter as well.

Actual feminine nouns are divided into four paradigms which form their plurals differently (-y -e -i) and one of them does stay the same in the nominative case (růže).

[Eburiden]

Why is it incorrect to say "These words are not good"?
For Czech having no actual article, I think it would be a more literal translation than with "the". Correct me, please, if I'm wrong.

[A_purrfect_cat]

That's a thing that was discussed a lot in earlier lessons. You need to use"the" or "those" for "ta", "these" is "tato" or "tahle" - duo is very consequent in that matter =)