adjective
- lacking in harmony between the different parts or elements; self-contradictory: an inconsistent story.
- lacking agreement, as one thing with another or two or more things in relation to each other; at variance: a summary that is inconsistent with the previously stated facts.
- not consistent in principles, conduct, etc.: He’s so inconsistent we never know if he’ll be kind or cruel.
- acting at variance with professed principles.
- Logic. incompatible(def 4b).
adjective
- lacking in consistency, agreement, or compatibility; at variance
- containing contradictory elements
- irregular or fickle in behaviour or mood
- Also: incompatible maths (of two or more equations) not having one common set of values of the variables: x + 2 y = 5 and x + 2 y = 6 are inconsistent
- logic (of a set of propositions) enabling an explicit contradiction to be validly derived
1640s, “not agreeing in substance or form,” from in- (1) “not, opposite of” + consistent. Related: Inconsistently.