There are multiple synonyms available for the word "inertly". Some of them include "passively", "indolently", "apathetically", "stagnantly", "idlely", "dormantly", "lazily", "sluggishly", "unresponsively", "motionlessly", and "lifelessly". All these words denote a state of inactivity, a lack of movement or response. The use of these synonyms helps to convey a sense of passivity or disengagement from activity, indicating a lack of energy or motivation. For instance, one could use these synonyms when describing someone who is uninterested in a conversation or an employee who is unproductive at work. The choice of synonym will depend on the context and tone of the sentence.