It depends on the context. I’ve noticed Chinese people on this site sometimes use the word out of context, causing *potential* misunderstandings. The basic sense of the word is indeed positive, meaning “humorous,” but it can also mean “strange.” If a person “looks funny,” that usually means they look strange. If something “smells funny,” it’s definitely bad. In most other contexts, “funny” is usually good, or at worst, ambiguous.

In some contexts 'funny' can mean strange or odd in some way. But it normally means humorous, makes you laugh. It would be a complement if the person was deliberately being funny, but impolite if something about them made you laugh but they were not trying to be funny. It's the difference between laughing WITH and laughing AT

First of all, funny is adjective and fun can be used as noun and adjective both, depending upon the context. If someone is making you laugh, you could, "(S)He is funny," or "He/She is a fun guy/girl to be with." Btw your Chinese teacher was wrong, you can never be derogatory or condescending if you're commenting someone funny. It's a compliment I believe. Regards, Zoayb

That depends on the context. For example: "That was so funny, haha." This sentence indicates that it was indeed something humorous. "That was not funny at all." This sencence shows rejection towards a situation that was probably meant to be funny, but turned out wrong, like a prank or a bad joke. "It smells/looks funny." As Phil has already told you, in this case funny could mean disgusting/bad, weird or strange. In a spoken form, if you are told "How funny" in a bored tone of voice, it could also be a sarcastic way to say that there was nothing funny about whatever was meant to be funny.

It really depends on the situation