To be thin-skinned is to be sensitive, especially to criticism and slights. Thin-skinned people are quick to take offense.

If your skin is literally thin, soft, and tender, like a baby's is, then you're going to be hurt more easily if you get scraped or cut. Similarly, a thin-skinned person gets emotionally hurt more often than most people. If you're thin-skinned, you take criticism, rejection, disappointment, and failure very hard. Being left out of anything could be perceived as a major insult. If you forget a thin-skinned person's birthday, they’ll probably hold a grudge.

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