one who attacks or assails; an aggressor; an assailant.

an illegal occupant of an estate, part of the country, etc.

aggressive - a) having the tendency of being aggressive; inclined to aggress; b) ready or willing to take issue or engage in direct action; militant.

full of enterprise and initiative; bold and active; pushing.

= ಆಕ್ರಮಣಕಾರ.