tar2 past tense and past participle tarred, present participle tarring [transitive]
to cover a surface with tar:
a tarred roof
if someone is tarred with the same brush as someone else, people think they have the same faults or have committed the same crimes, even if they have not:
You've made it very clear that you think I'm tarred with the same brush as William.
to cover someone in tar and feathers as a cruel unofficial punishment