To assert or promote one's opinion; to make one's thoughts known.(verb)
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Use "speak out" in a sentence
"She met Mr. Sakharov, who was using his prominence to speak out for human rights, at a trial of some activists in 1970."
"Non-Muslims have a limited capacity to influence this, though we can provide support to mainstream Muslims in their efforts to speak out against extremism."
"But, though the thirty-ninth president later acknowledged as accurate the criticisms of Brzezinski as being aggressive and ambitious, and inclined to speak out too forcefully on critical subjects, Carter clearly wanted him anyway."