bliss
Perfect happiness and peaceful, worry-free joy.
Bliss is complete happiness, a feeling of pure joy without any worry or trouble mixed in. When you sink into your favorite chair with a good book on a rainy Saturday, or take that first bite of your grandmother's homemade pie, or finally solve a puzzle you've been working on for days, you might feel a flash of bliss.
The word describes happiness so complete that nothing else matters in that moment. Bliss is total contentment, a feeling of being utterly satisfied and at peace. A cat stretched out in a sunny window experiences bliss. A swimmer floating peacefully in warm ocean water might feel blissful. When authors describe a character in a state of bliss, they mean that person feels utterly content and at peace.
People often talk about blissful ignorance, which means being happy specifically because you don't know about some problem or worry. If you're having a wonderful day at the park, blissfully unaware that you left your homework at school, you're experiencing happiness that comes from not knowing what's waiting for you later.
The word carries a sense of being completely absorbed in the good feeling, with no part of your mind wandering to worries or tasks. Pure bliss is rare and worth noticing when it happens.