This is the 13125th most frequent Swedish word.
tillsätta
"To appoint" or "to add" (depending on context).
Here, 'tillsätta' means 'to appoint someone to a specific position.'
Vi behöver tillsätta en ny chef för avdelningen.
We need to appoint a new manager for the department.
In this usage, 'tillsätta' refers to adding an ingredient to a mixture, like cooking.
Du bör tillsätta lite salt i soppan för att förbättra smaken.
You should add a little salt to the soup to improve the flavor.
Here, 'tillsätta' implies the action of implementing or applying something in a broader sense.