Antonyms of adj passionate

1 sense of passionate

Sense 1
passionate (vs. passionless) -- (having or expressing strong emotions)

passionless (vs. passionate) -- (not passionate; "passionless observation of human nature")
        => platonic -- (free from physical desire; "platonic love")
        => unimpassioned -- (free from emotional appeal; marked by reasonableness; "answered with an unimpassioned defense"; "the unimpassioned intellect")

Similarity of adj passionate

1 sense of passionate

Sense 1
passionate (vs. passionless) -- (having or expressing strong emotions)
       => ablaze, aflame, aroused -- (keenly excited (especially sexually) or indicating excitement; "his face all ablaze with excitement"- Bram Stoker; "he was aflame with desire")
       => ardent, fervent, fervid, fiery, impassioned, perfervid, torrid -- (characterized by intense emotion; "ardent love"; "an ardent lover"; "a fervent desire to change society"; "a fervent admirer"; "fiery oratory"; "an impassioned appeal"; "a torrid love affair")
       => choleric -- (easily moved to anger; "men of the choleric type take to kicking and smashing"- H.G.Wells)
       => demon-ridden -- (as if possessed by demons)
       => fanatic, fanatical, overzealous, rabid -- (marked by excessive enthusiasm for and intense devotion to a cause or idea; "rabid isolationist")
       => lustful, lusty, concupiscent -- (vigorously passionate)
       => wild -- (in a state of extreme emotion; "wild with anger"; "wild with grief")
          Also See-> emotional#2; enthusiastic#1; hot#3; loving#1