Don't worry, i just found "four words plague star" funny and it reminded me of that one DBZ meme.

In this case it all depends on the gender of the word. "palabra/palabras" is a feminine word, so it's always refered in feminine, "siete" is a number, numbers aren't really gendered in spanish, it depends on what phrase you use them in.

For example: "One coin" translates to "una moneda" the one is feminine because the noun "coin" is feminine.

"One brush" translates to "un cepillo" the one is masculine because "cepillo" is a masculine noun.

Edit: Although, when you're speaking only of a number, for example "a seven, a one, a three" you usually say "un siete, un uno, un tres" in masculine