Inconsistency (noun)

1. The state or quality of being inconsistent; lack of agreement or compatibility.
2. A failure to be logical, uniform, or steady.
3. An instance of inconsistency or conflicting behavior.

Origin:

Late 16th century, from in- "not" + consistent.

Examples:

1. The inconsistency in his statements raised doubts about his credibility.
2. The inconsistency of the data was a major problem for the research.
3. The inconsistency in the application of the rules was causing confusion.
4. The inconsistency of his behavior was a source of frustration for his friends and family.
5. The inconsistency of the results led the scientists to question their methods.