When his fellow panelists pushed back, he proceeded to pooh-pooh all those “experts” who have said otherwise.
The pope may pooh-pooh the decision to remain childless, but the world needs more people who choose pets over kids.
"to dismiss lightly and contemptuously," 1827, a slang reduplication of dismissive expression pooh. Among the many 19th century theories of the origin of language was the Pooh-pooh theory (1860), which held that language grew from natural expressions of surprise, joy, pain, or grief.
To dismiss lightly and contemptuously; airily deprecate; deride: I don't poopoo his talent, just his character (1827+)