IPA: /ɪnˈæktɪvli/
KK: /ɪnˈæktɪvli/
In a way that shows no activity or effort; not doing anything active.
He sat inactively on the couch, watching TV all day.
Inactively → It is formed from "in-" (meaning not) and "active" (from Latin "activus", meaning to do or to act) and the suffix "-ly" (meaning in a manner). The word "inactively" means in a manner that is not active or not engaged in action.
Think of 'not' ('in-') doing something ('active') — that's why inactively means not engaging in action.