Final answer:
Anxiety or trepidation describes a nervous or fearful feeling of uncertain agitation, often linked to the fight-or-flight response or high levels of neuroticism, and can manifest as physical symptoms impacting daily life.
Step-by-step explanation:
The term you are looking for to describe a nervous or fearful feeling of uncertain agitation is typically referred to as anxiety or trepidation. This feeling can be triggered by a fight-or-flight response, an involuntary reaction that prepares the body to either confront or avoid perceived danger. Modern psychological understanding recognizes that such feelings may not always have a clear cause; they can be part of a condition such as generalized anxiety disorder, where individuals experience prolonged feelings of worry and fearfulness.
Furthermore, a person high in neuroticism might experience such feelings more intensely, as they tend to have a greater tendency to experience negative emotions. These feelings can also manifest physically through symptoms like a racing heartbeat or sweating and can be severe enough to interfere with daily life, as seen in extreme cases like night terrors or panic attacks.