I find dictionaries tend to provide definitions that are too general and don't cut to the heart of how words are distinctly used. Is there a dictionary that does a better job defining words or providing examples as to illustrate the particular nuance in how words tend to be used?
As noted in comments, OED is peerless and M-W perhaps the best free online source, though other dictionaries now provide useful usage notes. No descriptive dictionary can be fully comprehensive; it would be colossal and nigh-on unsearchable (and out of date within a week).
Websites like ELU and Wordwizard tackle polysemy, including clashing (stipulative) definitions (polysemy with hypernymy, or conflicting usages). But again, total accuracy, reasonable sampling, and authoritativeness cannot be assumed.