The state, quality, or condition of being glad; gladness or happiness.
From glad plus -ship, a suffix creating abstract nouns for states, qualities, or conditions (as in friendship, hardship, leadership). This is an archaic or rare formation in English.
This is such an old-fashioned word that you'd almost never hear it in modern English—we've completely replaced it with simpler words like 'gladness,' 'joy,' or 'happiness.' But it shows how flexible English word-building was: you could stick -ship on almost any adjective to make it abstract!
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