Feeling sorry for someone and understanding their feelings.
Sympathising is a kind and caring feeling. It means you understand how someone feels and you want to help them.
Examples:
I am sympathising with my friend who is sad.
She is sympathising with her sister who is hurt.
They are sympathising with the dog who is lost.
We are sympathising with the baby who dropped their ice cream.
He is sympathising with the bird who cannot find its nest.
You sympathising with the cat who is stuck in the tree!