Merry means cheerful and full of good spirits. A merry laugh, a merry party, Merry Christmas.
In modern English it survives mostly in that last phrase and in a few fixed expressions, and it sounds old-fashioned anywhere else — nobody describes a colleague as merry. There is one very live informal British use: merry means slightly drunk, in a happy way, and it is the polite word for it. Note make merry, meaning to celebrate, which is deliberately archaic, and the Merry Men of Robin Hood, which is where most children meet the word.
1adjectivemerryCheerful and lively.
“It was a merry evening by any measure.”
2adjectiveslightlySlightly drunk, in British informal use.
“He was rather merry by the time the speeches started.”
Too few real examples of this word to estimate which sense is commonest.
merry is a cheerful state.
Old English myrge meant pleasant, and behind it is a Proto-Indo-European root meaning short — the idea being that a pleasant time seems to pass quickly. Mirth is the noun from the same word, and it has kept more of its life than merry has.
Middle English
mery
English, today
merry
Built from
From Middle English mery. From Middle English myrie, merie, mery, from Old English myrġe, myriġe (“pleasing, agreeable; pleasant, sweet, delightful; melodious”), from Proto-West Germanic murgī (“short, slow, leisurely”), from Proto-Germanic murguz (“short, slow”), from Proto-Indo-European mréǵʰus (“short”). Cognate with Scots mery, mirry (“merry”), Middle Dutch mergelijc (“pleasant, agreeable, joyful”), Norwegian - dialectal myrjel (“small object, figurine”), Latin brevis (“short, small, narrow, shallow”), Ancient Greek βραχύς (“short”). a doublet of brief.
Etymology from Wiktionary, CC BY-SA