Aspirate (pronounced AS-pih-rit) refers to fluid, tissue, or other substance that is withdrawn from a body cavity, cyst, or tumor. Aspirate (pronounced AS-pih-rayt) refers to the act of withdrawing the fluid, tissue, or other substance through a needle. It also refers to the accidental breathing in of food or fluid into the lungs. This can cause serious problems, such as pneumonia and other lung problems.