1. not passionate

- passionless observation of human nature

Similar word(s): unemotional, unenthusiastic, cold, platonic, unimpassioned

2. unmoved by feeling

- this passionless girl was like an icicle in the sunshine

Similar word(s): cold, emotionless

Sentences with passionless as an adjective:

- The lecturer had a cold, passionless approach towards his subject.

- This Valentine's Day was the most passionless ever for me.