The state or quality of having no dreams during sleep.
From Middle English dremen (to dream) + Old English -less (without) + -ness (state of being). The suffix -less entered English from Old Norse laus, meaning 'loose' or 'free from,' and -ness is a Germanic suffix that nominalizes adjectives.
Interestingly, dreamlessness doesn't actually mean you didn't dream—neuroscience shows humans dream multiple times each night during REM sleep, but dreamlessness describes the subjective experience of not remembering dreams, which is far more common than most people realize.
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