Unreliableness is a characteristic that pertains to the lack of trustworthiness in an individual or thing. Synonyms for unreliableness include instability, inconsistency, unpredictability, and untrustworthiness. Someone who exhibits unreliability can also be referred to as an untrustworthy person, an erratic individual, or an unreliable source. Other synonyms include undependability, unreliability, and fickleness. Traits such as unreliability and inconsistency undermine credibility, trustworthiness, and reliability. Being dependable and trustworthy is regarded as an essential attribute in any person or system, and so words that describe the opposite trait must be understood in order to identify and avoid the pitfalls associated with it.