IPA: /ɪmˈpæsəblɪ/
KK: /ɪmˈpæsəblɪ/
In a way that shows no emotion or feeling; unable to be affected by emotions or feelings.
She stared impassibly at the news, showing no sign of distress.
Impassibly → It is formed from "im-" (meaning not) and "passibilis" (from Latin, meaning able to be passed or suffered) and the suffix "-ly" (meaning in a manner). The word "impassibly" means in a manner that cannot be passed or suffered, often referring to a state of being unaffected or unyielding.
Think of 'not' ('im-') being able to be 'passed' ('passibilis') — that's why impassibly means in a way that cannot be affected.