Greenish blue is a color often associated with calmness and tranquility. However, there are several antonyms for greenish blue that depict different emotions and moods. One antonym for greenish blue is red, a color associated with passion, excitement, and energy. Another antonym for greenish blue is yellow, which is bright and cheerful, often associated with happiness and joy. Brown is also an antonym for greenish blue, a color that suggests earthiness and simplicity. Purple, on the other hand, represents luxury and sophistication, making it another antonym for greenish blue. Finally, black is an antonym for greenish blue that signifies mystery and elegance, often associated with power and authority.