What does "non-issue" mean?

A matter of no concern, especially one that had been of concern.

What is a synonym for "non-issue"?

Common synonyms include: dead letter.

noun

noun ·Rare ·Advanced level

Noun

1
A matter of no concern, especially one that had been of concern.
"His position on that matter is a non-issue, now that the courts have decided."
2
the state of something that has outlived its relevance wordnet

"His position on that matter is a non-issue, now that the courts have decided."

From non- + issue.