IPA: /ˈpæʃənləs/
KK: /ˈpæʃənləs/
Not having strong feelings or emotions; showing little enthusiasm or excitement.
His passionless response to the news surprised everyone.
Comparative: more passionless
Superlative: most passionless
Passionless → It is formed from "passion" (from Latin *passio*, meaning suffering or feeling) and "-less" (meaning without). The word "passionless" means without passion or emotion.
Think of being 'without' ('-less') any 'feeling' ('passio') — that's why passionless means lacking emotion.