To evaluate the expression \( \sqrt{19} - 32 \):
- \( \sqrt{19} \) is an irrational number because 19 is not a perfect square.
- When you subtract 32 (a whole number and also an integer) from an irrational number, the result remains irrational.
Therefore, the expression \( \sqrt{19} - 32 \) will result in an irrational number.
The answer is: an irrational number.