IPA: /ˈɪn.də.ləns/
KK: /ˈɪn.də.ləns/
A tendency to avoid work or activity; a state of being lazy.
His indolence prevented him from completing his assignments on time.
Indolence is formed from "in-" (meaning not) and "dolere" (meaning to feel pain or grief). The word describes a state of being where one is not feeling pain, which metaphorically extends to a lack of activity or effort, hence laziness.
Think of 'not feeling pain' ('in-' means not and 'dolere' means to feel pain) to remember that indolence refers to a state of laziness or inactivity.