prosiest

/P R OW1 Z IY0 AH0 S T/
adjective
  1. 1

    Unpoetic (of speech or writing); dull and unimaginative.

  2. 2

    Behaving in a dull way (of a person); boring, tedious.

Source: https://en.wiktionary.org/wiki/prosiest, https://en.wiktionary.org/wiki/prosy