1
general::
Put up with the worst of some bad circumstance, as in It was the secretary who had to bear the brunt of the doctor's anger. This idiom uses brunt in the sense of "the main force of an enemy's attack," which was sustained by the front lines of the defenders. [Second half of 1700s]
American Heritage Idioms
2
general::
Phrase(s): bear the brunt (of something)
to withstand the worst part or the strongest part of something, such as an attack. • I had to bear the brunt of her screaming and yelling. • Why don’t you talk with her the next time she complains? I’m tired of bearing the brunt of her objections.
McGrawhill's American Idioms And Phrasal Verbs