kuài lè / hé / gāo xìng / shì / jìn yì cí / dàn / bù / wán quán / tóng yì

“快乐”和“高兴”是近义词，但不完全同义。

The words 'kuài lè' and 'gāo xìng' are near-synonyms, but they are not completely synonymous.