Write the Word or Phrase That Best Completes Each Statement $$\text { The function given by } f ( x ) = - 3 x ^ { 5 } + 2 \sqrt { x } + \frac { 2 } { x } \text { (is/is not) a polynomial function. }$$

Write the word or phrase that best completes each statement or answers the question.
Provide the missing information.
- $$\text { The function given by } f ( x ) = - 3 x ^ { 5 } + 2 \sqrt { x } + \frac { 2 } { x } \text { (is/is not) a polynomial function. }$$