A person who secedes or supports secession from a political union or an alliance or organisation.(noun)
Seceding or supporting secession.(adjective)
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Use "secessionist" in a sentence
"When most knowledgeable Americans hear the word secessionist, they think of the southern slave states that formed the Confederacy and seceded from the United States back in 1861."
"Meanwhile, the Namibian government has called the secessionist movement a "terrorist" conspiracy and accused Muyongo and Mamili of instigating it."
"But he still would not go along with the rest of the South in the secession movement and even refusing to call a secessionist convention till he was forced to do so."