True-blue describes someone completely loyal and dependable, the kind of person who stands by you no matter what happens. A true-blue friend doesn't abandon you when things get difficult or when being your friend stops being convenient. They stick with you through arguments, disappointments, and challenges.

The phrase comes from a type of blue dye that didn't fade or wash out, unlike cheaper dyes that would lose their color. Just as that dye stayed blue through many washings, a true-blue person stays loyal through many tests.

You might say your dog is true-blue because she waits by the door every day for you to come home, or that your best friend proved himself true-blue when he defended you against unfair criticism. A true-blue teammate shows up to every practice, even the cold early-morning ones. A true-blue fan supports their team through losing seasons as much as championship years.

The word suggests more than casual friendship. It means steadfast commitment and unwavering loyalty, the kind that gets proven over time through actions, not just words.