sep ‧ a ‧ ra ‧ tist /ˈsep ə rətəst, ˈsep ə rətɪst/ BrE AmE noun [countable]
[ Word Family: noun : ↑ separation , ↑ separates , ↑ separatist , ↑ separatism , ↑ separator , inseperability; adjective : ↑ separable ≠ ↑ inseparable , ↑ separate , ↑ separated ; adverb : ↑ inseparably , ↑ separately ; verb : ↑ separate ]
someone who belongs to a group that wants to start a new country with its own government, by separating from the country that they belong to now
—separatism noun [uncountable]