Feeling sad, unhappy, or without gladness; the opposite of glad.
From glad (from Old English glæd, meaning bright, shining, happy) plus the suffix -less (meaning without). This is a straightforward English word formation meaning 'without gladness.'
While 'sad' and 'unhappy' are common words we use, 'gladless' is the poetic or archaic way to say it—you'll find it in older literature, but modern English speakers have abandoned it in favor of simpler words. Language is always pruning words it doesn't need!
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