Used as a noun to describe something or someone that is repulsing to you either by action or nature. It can also be used as a complete sentance in response to information received.
As a noun:
Indian food is disgustable.
The work he did on my house is disgustable.
As a response to information received:
Party A:Giovanni cheated on his wife, contracted an STD, and passed it on to his wife not knowing.
Part B: Disgustable!