Unashamed describes someone who feels no embarrassment about something that other people might frown at — and, crucially, does not hide it. The word carries a small charge because it assumes an audience with an opinion. You would not say "I am unashamed of brushing my teeth"; you say it about the thing someone could be expected to apologise for. "He is unashamed about leaving school at fifteen." "She is an unashamed fan of very bad pop music." That second pattern is extremely common and mostly warm or funny: unashamed romantic, unashamed nostalgia, unashamed luxury. Used that way it is close to "proudly, openly, no apology needed", and it often praises the person's honesty. But the same word turns cold when the thing really is bad: "unashamed greed", "an unashamed lie" — now it means the person should feel shame and does not, which is worse than doing it quietly. So the tone comes from what follows the word, not from the word itself. Grammatically it likes "about" or "of" after it, or it sits in front of a noun.

不覺得羞恥的、大方承認的（可褒可貶：褒是「坦然、不遮掩」，貶是「厚臉皮、毫不知恥」）。