The quality or state of being late, overdue, or happening after the proper or expected time.
From 'belated' (adjective) plus '-ness' (nominalizing suffix that converts adjectives to nouns). The root chain goes: be- + late + -ed (adjective marker) + -ness (abstraction marker).
The suffix '-ness' is so powerful that English speakers can add it to almost any adjective to create a noun—'belatedness,' 'slowness,' 'brightness'—allowing us to discuss abstract qualities as concrete things.
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