Here are some possible interpretations:
* Misspelling of "Ghost": "Ghost" is often written as "ゴースト" (go-suto) in Japanese.
* Misspelling of "Gothic": "Gothic" is sometimes written as "ゴシック" (go-shikku), but it's possible someone mistakenly spelled it as "go-suto".
* Made-up word: It's possible that "go-suto" is a word created for a specific purpose, like in a story, song, or online game.
To understand the meaning of "go-suto", you need more context. For example, where did you see or hear this word? What was the situation?
Please provide more information so I can help you understand the meaning better.