A phobia is an excessive, persistent fear of a specific thing. Excessive is important in this.
For example, it’s natural to be weary when you are in a position where you might fall and possibly get hurt. It’s a phobia when you freeze up in fear standing on a chair, because you could fall and hurt yourself.
Another common phobia is spiders, where fear of most spiders is completely unfounded, as the vast majority of spiders can’t actually really hurt humans.
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