true blue

/T R UW1 B L UW0/
noun
  1. 1

    A faithful partisan.

  2. 2

    A blue dye from Coventry, England, famous for not washing out.

adjective
  1. 1

    Steadfastly loyal or faithful, unwavering in loyalty.

    โ€œHe was a true blue supporter, and would not listen to what he supposed to be the lies of the opposition.โ€

  2. 2

    Authentic, undoubtedly true; honest.

Source: https://en.wiktionary.org/wiki/true%20blue