How to do anti-join or inverse join in bash

I want to perform what some data analysis software call an anti-join: remove from one list those lines matching lines in another list. Here is some toy data and the expected output:

$ echo -e "a\nb\nc\nd" > list1
$ echo -e "c\nd\ne\nf" > list2
$ antijoincommand list1 list2
a
b