sympathizer

1. (often derogatory) A person who sympathizes (with a political cause, a side in a conflict, etc.); a supporter.Examples: "His reputation was ruined when it was revealed that he had been a Nazi sympathizer before the war."; "[…] she exposed herself to the fury of the sympathizers with slavery, without fear, and suffered their blows without flinching."; "‘[…] And I tell you that the slightest suspicion of my loyalty could be ruin for me, ruin! If it were ever breathed that I were even a sympathiser with this rebellion, there iss an end of me.’"derogatoryoften

2. (now rare) A person who has, shows or expresses sympathy (with another person or people); a person who enters into the feelings of another.Examples: "[…] it is a sad case when the truly godly, who are cordial sympathizers, and earnest intercessours in the straits of a Nation, are stricken dumb in a day of calamity […]"; "[…] I am a sympathizer in every part of thy distress, except (and yet it is cruel to say it) in That which arises from thy guilt."; "Not a mood of his but what found a ready sympathiser in Margaret; not a wish of his that she did not strive to forecast, and to fulfil."archaic