The underlined word in the sentence is "blue".
Answer:
In the sentence, "blue" means "sad".
Explanation:
We often associate the word "blue" to the color blue. But in English, "blue" can have different meanings. In the sentence "When I failed the test, it made me really blue," it is clear that the person did not literally turn blue after failing a test. In this case, the context reveals that "blue" is a different way of saying "sad" or "melancholy". The speaker in the sentence was sad after failing the test.
