These words refer to something that stands out in vivid or sharp relief from its surroundings. Clear is the most general and informal of these words. It suggests something that is not the least bit confused, vague or fuzzy, and therefore easy to understand or perceive: clear directions on how to reach the hotel; the clear lettering of the had made poster. Whereas clear may emphasize lack of confusion or ambiguity, distinct is restricted to sharpness of impression or lack of blur: instructions that were clear enough if only she had spoken in a more distinct voice. Distinct can also suggest well-defined outlines: the right focus for getting a distinct image. Or it can suggest something that stands out noticeably: the distinct note of annoyance in her voice.

Definite relates to the lack of ambiguity implied by clear and to the sharpness of outline or impression implied by distinct : setting up definite rules of procedure; a definite litmus reaction that proved the presence of acidity. Unmistakable intensifies the implication of distinct and suggests a noticeable forcefulness not to be overlooked; the word emphasizes the presence of evidence that removes all possibility for doubt: an unmistakable nod of her head; the unmistakable wail of a siren.