How do you say "happy" in Thai?

The term "happy" in Thai is accurately conveyed with the phrase "มีความสุข" (mee khwam suk). This phrase directly translates to "to have happiness," which effectively encapsulates the concept of being happy.

The reason this is the correct choice lies in the meaning of the individual components: "มี" (mee) means "to have," and "ความสุข" (khwam suk) translates to "happiness." Together, they express the state of experiencing happiness or joy, making this expression the appropriate choice for conveying the word "happy."

The other options do not relate to the concept of happiness. "เศร้า" (sao) means "sad," "เรียน" (rian) translates to "to study" or "to learn," and "คิดถึง" (khit thueng) means "to miss" or "to long for." Each of these words has a distinct meaning that does not reflect the sentiment of happiness.