set yourself up as something

Từ điển tiếng Anh - Cambridge Advanced Learners Dictionary

set yourself up as sth phrasal verb reflexive often disapproving [ setting yourself up as sth sets yourself up as sth ]
to say that you are a particular type of person
• He sets himself up as an expert on vegetable growing, but he doesn't seem to me to know much about it.
Thesaurus⁺: ↑Assertions and asserting
Main entry: set_{phrasal verb}