single word requests - Is there an adjective to describe someone who feels the desire to run away from situations?

When a horse is in a mood where he's prone to jump or bolt at the slightest disturbance, we describe him as:

• skittish


• jumpy


• spooked¹

When a person so acts, we more typically describe him as:

• anxious


• nervous

Or, in more literary or quasi-psychological contexts:

• high-strung

Much less commonly, you have the rare and somewhat counterintuitive (based on modern meanings of related words):

• excitable


• restive

Personally, I'd go with skittish.

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¹ _{I know it would make more sense to describe him as spookable, but usage prefers to describe it in the past tense, as a state of mind the horse is in after being spooked for the first time.}

If this bugs you, you could find a middle ground in easily spooked.