interjection
pshaw
puh-SHAW/pʃˈaʊ/
An exclamation dismissing something as unworthy of attention.
Pshaw, that little trophy is nothing to boast about.

Etymology
Pshaw is documented as an exclamation of contempt, impatience, or rejection. The evidence establishes this dismissive use but supplies no earlier form from which to explain its origin.
In context
Pshaw, those people online know nothing! Don't worry, you'll learn well later, I can't do without you in the future.
More examples
- Pshaw, a little rain won't spoil our picnic.
- Pshaw, you don't owe me anything for such a small favor.
- “Pshaw,” he says when I mention the latest gossip.