It's a very common word used to refer to any type of liquid consumed for refreshment, including:
* Water
* Juice
* Soda
* Coffee
* Tea
* Alcohol
You might hear it in phrases like:
* "Nipe kinywaji, tafadhali." (Give me a drink, please.)
* "Nina kiu, nataka kinywaji." (I'm thirsty, I want a drink.)
* "Hiki ni kinywaji cha kupendeza." (This is a delicious drink.)