(informal) A person who practises happy slapping.

(US, Canada) A greeting used during the Christmas and winter holiday season to recognize the celebration of many holidays, sometimes starting with Thanksgiving and including Hanukkah, the winter solstice, Christmas, Kwanzaa, and New Year's Day.

plural of happy slapping

(Britain) A children's card game played with a pack of 44 picture cards that depict a father, mother son and daughter of 11 families mostly having occupational surnames (e.g. Mr Bun the Baker); players have to collect entire families

(literature) A clichéd conclusion in which all loose ends are tied up and all main characters are content.

(simile) Extremely happy and carefree

(simile) Very happy and carefree.

Said or written to a person who is celebrating his or her birthday in order to convey the good wishes of the speaker or writer (literally, "may you have a happy birthday")

(colloquial, transitive) To wish (someone) a happy birthday.

plural of happy hour