protester

As a noun protester

is one who protests, either singly or in a public display of group feeling.

As a verb protested is

past tense of protest.

As nouns the difference between protestant and protester

is that protestant is one who protests; a protester while protester is one who protests, either singly or in a public display of group feeling.

As an adjective protestant

is alternative case form of Protestant|lang=en.

As nouns the difference between protester and activist

is that protester is one who protests, either singly or in a public display of group feeling while activist is one who is politically active in the role of a citizen; especially, one who campaigns for change.

As an adjective activist is

behaving as an activist.

As nouns the difference between protester and protestator

is that protester is one who protests, either singly or in a public display of group feeling while protestator is (obsolete) one who makes protestation; a protester.

As nouns the difference between protester and kettling

is that protester is one who protests, either singly or in a public display of group feeling while kettling is a crowd control technique, used by police, where a hostile group of protesters or rioters are surrounded and not allowed to disperse, sometimes with the use of temporary fencing to corral and isolate portions of the group.