The Greenwood is a 4 door vehicle in Manhunt 2, Grand Theft Auto: Vice City, Grand Theft Auto: San Andreas and Grand Theft Auto: Vice City Stories. In Manhunt 2, it appears only in the level Sexual Deviants.
The Greenwood bears a strong resemblance to an mid/late-80's Dodge Diplomat, Plymouth Gran Fury, or a Chrysler Fifth Avenue. The grille, vinyl roof and headlights are closer to the Fifth Avenue. The back doors could either be from the Diplomat or Gran Fury.