Which ending typically go with masculine nouns? ( more than 1 response

The letter "o." For example, in the phrase "Eres estupido," (sure it's a bit mean but,) this would go for men. Saying "Eres estupida," would go for women. A lot of Spanish words have "o" at the end of the word to indicate it's directed towards men. Same goes for women, with the letter "a."

Here are some phrases in masculine and feminine form.

"Eres estupido," vs. "Eres estupida."

"Eres guapo," vs. "Eres guapa."

"Nino," vs. "Nina."

"Eso es toxico," vs. "Eso es toxica."'

Hope that helps! :)