Orig., blithesomeness; gladness; now, the highest degree of happiness; blessedness; exalted felicity; heavenly joy. [1913 Webster]
"An then at last our bliss
Full and perfect is." [1913 Webster]

bliss, n.
1 a perfect joy or happiness. b enjoyment; gladness.
2 a being in heaven. b a state of blessedness.

Etymology:
OE bliths, bliss f. Gmc blithsjo f. blithiz BLITHE: sense infl. by BLESS

N  pleasure, gratification, enjoyment, fruition, oblectation, delectation, delection, relish, zest, gusto, satisfaction, complacency, well-being, good, snugness, comfort, ease, cushion, sans souci, without worry, mind at ease, joy, gladness, delight, glee, cheer, sunshine, cheerfulness, treat, refreshment, amusement, luxury, mens sana in corpore sano, a sound mind in a sound body, happiness, felicity, bliss, beatitude, beautification, enchantment, transport, rapture, ravishment, ecstasy, summum bonum, paradise, elysium, third heaven, seventh heaven, cloud nine, unalloyed happiness, hedonics, hedonism, honeymoon, palmy days, halcyon days, golden age, golden time, Dixie, Dixie's land, Saturnia regna, Arcadia, Shangri-La, happy valley, Agapemone, pleased, not sorry, glad, gladsome, pleased as Punch, happy, blest, blessed, blissful, beatified, happy as a clam at high water, happy as a clam, happy as a king, happy as the day is long, thrice happy, ter quaterque beatus, enjoying, joyful, hedonic, in a blissful state, in paradise, in raptures, in ecstasies, in a transport of delight, comfortable, at ease, content, sans souci, overjoyed, entranced, enchanted, enraptures, enravished, transported, fascinated, captivated, with a joyful face, with sparkling eyes, pleasing, ecstatic, beatic, painless, unalloyed, without alloy, cloudless, happily, with pleasure, with glee, one's heart leaping with joy, a wilderness of sweets, I wish you all the joy that you can wish, jour de ma vie, joy ruled the day and love the night, joys season'd high and tasting strong of guilt, oh happiness, our being's end and aim!, there is a pleasure that is born of pain, throned on highest bliss, vedi Napoli e poi muori, zwischen Freud und Leid ist die Brucke nicht weit, the bridge between joy and sorrow is not wide.