/prɪˈpɑːstərəs/

pre·pos·ter·ous

BrE /prɪˈpɒstərəs/

NAmE /prɪˈpɑːstərəs/

(formal)

completely unreasonable, especially in a way that is shocking or annoying

SYN outrageous

These claims are absolutely preposterous!

unusual in a silly or shocking way

SYN outrageous

The band were famous for their preposterous clothes and haircuts.

▸

pre·pos·ter·ous·ly

BrE /prɪˈpɒstərəsli/

NAmE /prɪˈpɑːstərəsli/

a preposterously expensive bottle of wine