'take after'

1`. This is the relative after whom I take.
2. This is the relative I take after.
What is the meaning of these sentences?
What is the meaning for ‘take after’?
Please comment.

Only (2) is correct using this idiom.
The relative must be older than you.
If they were younger than you then the reverse would be the case - This is the relative who takes after me.

It means that you are like them - you either look like them, act like them, have the same type of personality as them or have the same interests and likes as them.