1) Cold 2) Emotionless 3) Unemotional 4) Unenthusiastic 5) Unimpassioned 1) Cold 2) Not passionate 3) Platonic 4) Showing no emotion 5) Unemotional 6) Unenthusiastic 7) Unimpassioned 8) Unmoved by feeling 
• (a.) Void of passion; without anger or emotion; not easily excited; calm.
Pas'sion·less adjective Void of passion; without anger or emotion; not easily excited; calm. 'Self-contained and passionless .' Tennyson. 
[adj] - not passionate
passionless 1. Without passion. 2. In medicine, painless, without suffering.
adjective not passionate; `passionless observation of human nature`