A few of the translation apps I use show both to mean happy. Are these synonyms or is there a deeper level for one, like joy might be considered deeper than happy?
高 = highly; 兴= delighted
高兴 = happy; glad; delighted
describe a emotional state of being delighted
开= open; 心 = heart
开心 = happy; joyful
metaphorically describe an effect of being happy
Both 高兴 and 开心 means 'happy', but with different emphasis.
For example, if you are glad that you didn't get killed in a car accident, you can say: "我很高興我還活著" (I am glad that I am still alive), but you wouldn't say: "我很開心我還活著" (I am joyful that I am still alive)
Another example, We use 我很高興見到你 (I am glad to see you) as a polite greeting, but "見到你我很開心" (seeing you make me happy) would be a more passionate expression.
- 开心 is also more personal, e.g. "今天是我最开心的一天" is more natural than "今天是我最高興的一天"
Another word for 'happy:
快 = satisfactory; 樂 = delight
快樂 = happy/ joyful/ cheerful (describe a joyful emotional state). It can be a noun or an adjective
- 高兴[gāo xìng]
- (愉快而兴奋) glad; happy; pleased; elated; joyful; cheerful:
- I'm very glad to see you. 我见到你很高兴。
- He is sure to be pleased [happy] at the news. 他听到这个消息一定很高兴。
- 开心[kāi xīn]
- （快乐; 舒畅） feel happy; rejoice; joyful; be delighted; have a grand time:
- His joy was immense. 他开心极了。
- The children dance round him in delight. 孩子们开心地围着他跳舞。
不管说哪一个都能 了解你的意思 no much difference, whichever you use could make people know you are happy
Just like the difference between Happy and Delighted/Pleased.
In a word, when comes to daily usage, no difference, unless bringing up to an academic/professional level.