Relating to or causing sleeplessness; something that prevents sleep.
From Greek agrypnos (sleepless) plus the suffix -otic (relating to), used in medical terminology since at least the 1600s to describe substances or conditions that induce wakefulness.
Coffee, caffeine, and stress are all agrypnotic—the word creates a formal medical opposite to 'hypnotic' drugs that put you to sleep, and it shows how many everyday things technically sabotage our rest.
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