<prompt> Phobia is defined asPalpitation on thinking about a definite entityExcessive unreasonable fear about a specific situationPerception without stimulationAltered perception  <response>: Phobia is defined as an irrational fear of a specific object, situation or activity, often leading o persistent avoidance of the feared object, situation or activity. Common types Agoraphobia Social phobia Specific phobia Ref: A sho textbook of psychiatry, Niraj Ahuja,7th edition, pg no 92 