inconsistent

Etymology

in- + consistent

adj

1. Not consistent:
   1. Not compatible (with another thing); incompatible, discrepant, at odds.
      His account of the evening was inconsistent with the security-camera footage.
   2. Lacking internal consistency; self-contradicting; not compatible with itself.
      He gave an inconsistent account of the evening, saying he called her before eight, but later that he had not talked to her until after nine.
      He was one of those men of inconsistent politics, governed at once by prejudice and sympathies, whose 'attitude' it is impossible to foretell. 1862, Robert Aspland, editor, The Christian Reformer
   3. Not consistent or coherent in thought or behavior.
      “Take him for better or worse,” added Mr. Lee, “and I think he is the strangest and most inconsistent man I ever saw.” “Inconsistent!” resumed Mr. Jones. “He is worse than inconsistent. Inconsistencies may be pardoned as constitutional defects …” 1848, The Columbian Magazine, volume 9, page 88
   4. (logic) Having the property that a contradiction can be derived.