IPA: /ˈθɜːrstɪli/
KK: /ˈθɜrˌsti li/
In a way that shows a strong desire for something, especially for a drink.
After running in the heat, she drank thirstily from her water bottle.
Thirstily → It is formed from "thirst" (from Old English "þirst", meaning a strong desire for liquid) and "-ily" (a suffix forming adverbs, meaning in a manner of). The word "thirstily" means in a manner that shows a strong desire for liquid.
Think of having a strong 'desire for liquid' ('thirst') and doing so 'in a manner' ('-ily'). This helps you remember that 'thirstily' describes how someone seeks to quench their thirst.