der Schwiegervater
father-in-law
The father of one's spouse or partner.
Mein Schwiegervater kommt am Wochenende zu Besuch.
My father-in-law is coming to visit this weekend.

father-in-law
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father-in-law
The father of one's spouse or partner.
Mein Schwiegervater kommt am Wochenende zu Besuch.
My father-in-law is coming to visit this weekend.

The word consists of the prefix 'Schwieger-' and the base word 'vater' (father). The prefix 'Schwieger-' always refers to a family relationship created by marriage.
Seit der Hochzeit meiner Tochter ist er mein Schwiegervater.
Since my daughter's wedding, he has been my father-in-law.
The component 'Schwieger-' is used for all family members by marriage. If you know this pattern, you will also understand 'Schwiegermutter' (mother-in-law), 'Schwiegersohn' (son-in-law), and 'Schwiegereltern' (parents-in-law).
Meine Schwiegereltern sind die Eltern meiner Frau.
My parents-in-law are my wife's parents.
Since it always concerns a relationship to a person, 'Schwiegervater' (father-in-law) is almost always used with a possessive article such as 'mein' (my), 'dein' (your), or 'ihr' (her/their).
Wie verstehst du dich mit deinem Schwiegervater?
How do you get along with your father-in-law?
father
'der Vater' and 'der Schwiegervater' both refer to a male relative in the family. 'der Vater' is your own male parent. 'der Schwiegervater' is the father of your spouse or partner. The words can be confusing because both describe a father role within the family. The important difference is the relationship: directly to the child, or through a marriage. So you say 'mein Vater' for your own parent and 'mein Schwiegervater' for the father of the person you are married to.

Karim hilft seinem Schwiegervater am Wochenende im Garten.
Karim helps his father-in-law in the garden on weekends.
Im Park hat mein Vater früher oft mit uns Fußball gespielt.
My father often used to play soccer with us in the park.