One who invades; an assailant; an encroacher; an intruder.(noun)
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Use "invader" in a sentence
"According to this logic, the occupied people must be held to a much higher standard of behavior than the invader should be – at least when the invader is the United States."
"History tells us that no matter how technologically advanced an invader is the people of Afghanistan always unite and prevail to fight each other another day while the Pakistanis in the NWP are Pashstun who are ethnically tied to a group of the Afghanistan people and probably possess their innate hatred of ferangi in their country."
"If the invader is offering insult or danger to others, you need to call on an organizer, or if you are an organizer, to escort the invader out and not let them back in."