pipe up

verb pipes up · piping up · piped up

1. intransitive To speak up, especially in a robust, assertive manner; to say something loudly and suddenly. "You seem to have a lot to say," remarked Silver, spitting far into the air. "Pipe up and let me hear it, or lay to."
2. intransitive To begin singing or playing musical notes on a pipe or similar wind instrument. [T]he frogs in a neighboring marsh began to pipe up for the evening concert.
3. intransitive, usually, of wind To begin to blow more vigorously. Once, for ten minutes, the sun shone at midday, and ten minutes afterward a new gale was piping up.
4. rare, transitive To call, awaken, or summon, as with a musical instrument. Yet beyond turning my blood cold for a moment, it gave me little trouble, for evil tales have hung about the church; and though I did not set much store by the old yarns of Blackbeard piping up his crew, yet I thought strange things might well go on among the graves at night. And so I never budged,

Opposite: pipe down