General meaning:
* Malawak: This is the most common and direct translation, meaning "wide" or "extensive".
* Malapad: This also means "wide" but can also be used to describe something flat and expansive.
* Malalaki: This means "big" or "large" and can be used to describe something vast in size.
Specific context:
* Malawak na karagatan: Vast ocean
* Malawak na kapatagan: Vast plains
* Malawak na kagubatan: Vast forest
* Malalaking halaga: Vast amounts (referring to money or quantities)
Other options:
* Walang hanggan: This literally means "without limits" and can be used to describe something vast and boundless.
* Napakalawak: This emphasizes the vastness and is a more emphatic way of saying "very wide".
The best translation for "vast" in Filipino will depend on the specific context and nuance you want to convey.