Passionate, a.
Etymology: [LL. passionatus: cf. F. passionné.]
1. Capable or susceptible of passion, or of different passions; easily moved, excited or agitated; specifically, easily moved to anger; irascible; quick-tempered; as, a passionate nature. Homer's Achilles is haughty and passionate. Prior.
2. Characterized by passion; expressing passion; ardent in feeling or desire; vehement; warm; as, a passionate friendship. "The passionate Pilgrim." Shak.
3. Suffering; sorrowful. [Obs.] Shak.
1 other Webster entry under this spelling
Passionate, v. i.
1. To affect with passion; to impassion. [Obs.] Great pleasure, mixed with pitiful regard, The godly kind and queen did passionate. Spenser.
2. To express feelingly or sorrowfully. [Obs.] Shak.
Shades of meaning
Fernald lists passionate only as an antonym, under calm.
He lists it without comment; the entries above explain its neighbors.