An irrational fear of an object or event is called a/an:

A) phobia.
B) compulsion.
C) panic.
D) obsession.

Phobia

Intense, irrational aversion or dread towards a particular object or situation.

Irrational Fear

An excessive and unreasonable fear response to a specific object, situation, or activity.

Object

In general terms, refers to any tangible or intangible entity; in psychology, it can also refer to a target of attention, thought, or affection.