Single word antonym of "premature"

Question

A friend of mine recently made a joke which was poorly timed; the visual irony had passed by the time she said it. I remarked that this joke was "postmature", then realized that isn't a word. Is there an antonym of premature, or can something never go past mature? For pregnancies, you can be overdue (thesaurus.com), but is there another such word that can also be extended to situations such as the one I had?

Note: I'm not looking for mature. I guess I'm asking this: can something pass maturity? Is there a word for that which can be used in a ubiquitous manner?

Answer 1

I think stale would be the word you're looking for concerning ubiquitous manner. https://www.vocabulary.com/dictionary/stale

Answer 2

Adjective: precocious pri'kow-shus

Characterized by or characteristic of exceptionally early development or maturity (especially in mental aptitude)

"a precocious child"; "a precocious achievement"

-- WordWeb Online

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It is not limited to mental development, though that is the most common sense when applied to humans.

• Hares are precocial: Their young are born with fur, sighted, and somewhat independent.

• Rabbits are altricial: Their young are born naked, blind, and dependent. You might think of them as relatively premature, in the sense that they are not as well developed as hares.