What is the meaning of Kosong?

Not having additional ingredients, such as milk or sugar; plain.

empty

vacant:

1. containing nothing

   containing nothing

   empty, not occupied.

   vacant (not occupied)

   empty, meaningless

   unavailable

   hollow (having an empty space or cavity inside)

   unimportant

   stupid

   unenthusiastic, unpassionate

   zero

   Not containing anything; empty.

   Vacant:

   1. Not filled.

      Not filled.

      Not occupied.

      Having an empty space or cavity inside; hollow.

      Having no importance; unimportant.

      Having no flavour; bland.

      The number zero or 0.

      Source: wiktionary.org