Is this the same as “I am unhappy” or is there a word in Indonesian for “unhappy”?
For me, as a non-native English speaker, these two things "not happy" & "unhappy" mean the same.
The prefix "un" is used to negate the word "happy".
That's how I see it.
As far as I know, Bahasa Indonesia does not have a prefix that is used to negate a word.
In this sentence, the word "tidak" is used to negate the word "happy".
Another word for "unhappy" could be "sad".
You could say it like this :
"Saya tidak bahagia, saya sedih"
"saya sedih' = I am sad.
"saya merasa sedih" = I feel sad.