縁起でもないこと言わないでよ

I understand the gist of the sentence. The speaker is saying something like
"Please don't say something so grim". But how does でも play into this? Why is
it not 縁起ないこと instead? So it would be like "thing with no luck".

The closest definition which makes sense to me is "~or something" for でも. But,
even if don't make sense because there is a lack of commas after でも
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2020-03-07T06:01:31.443
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2020-03-07T06:01:31.443
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question
grammar particle-でも
Clarification on the usage of でも in this sentence