"Highly sensitive" refers to individuals who possess a heightened sensitivity to external stimuli, including emotional, social, and environmental factors. This trait is often associated with the concept of highly sensitive person (HSP), which was popularized by psychologist Elaine Aron. HSPs may experience stronger reactions to sensory input, such as bright lights, loud noises, or strong smells. People who are highly sensitive may also be more attuned to the emotions of others, leading to increased empathy. This sensitivity can be both a strength and a challenge, as it allows for deep emotional connections but may also result in feeling overwhelmed in busy or chaotic environments.