(This phrasal verb has more than one meaning)
Definition: to make clothes smaller by altering them at the seams.
E.g.1. These trousers are too big, but I love them. I wonder if my mother could take them in for me.
E.g.2. Don’t worry, Sir. If the jacket is too large we can take it in. Let me measure you again.
This phrasal verb can be separated.