1. delighted, pleased, or glad, as over a particular thing: to be happy to see a person.
2. characterized by or indicative of pleasure, contentment, or joy: a happy mood; a happy frame of mind.
3. favored by fortune; fortunate or lucky: a happy, fruitful land.
4. apt or felicitous, as actions, utterances, or ideas.
5. obsessed by or quick to use the item indicated (usually used in combination): a trigger-happy gangster. Everybody is gadget-happy these days.