The adjective self-proclaimed means describing yourself in a certain way. Just because you're a self-proclaimed genius in the kitchen doesn't necessarily mean your family loves your creative recipes.
Being self-proclaimed means making an assertion about who you are or what you're skilled at. Sometimes that matches other people's perceptions: you're a self-proclaimed dog expert, and everyone comes to you for advice about their problematic pups. But often it stems from a skewed view of your own abilities. You may be a self-proclaimed Icelandic speaker, but if no one in Reykjavík can understand a word you say, it might be time to re-think the way you describe yourself!