To attack violently, as with blows or military force; assault.
To beset is to harass or have trouble on an ongoing basis from multiple sources or from all sides.
To start work on with purpose and vigor:
Find another word for set-upon. In this page you can discover 5 synonyms, antonyms, idiomatic expressions, and related words for set-upon, like: assail, beset, fall-upon, spring at and attack.