What does contradictory mean?
Contradictory describes things that are mutually opposed or inconsistent — statements, beliefs, pieces of evidence, or courses of action that cannot all be true or valid at the same time. A witness may give contradictory testimony; a policy may rest on contradictory assumptions. The word carries a neutral-to-critical tone depending on context: scientists speak matter-of-factly of contradictory results awaiting reconciliation, but describing someone's behaviour as contradictory often implies inconsistency or bad faith. In formal logic, contradictory has a precise technical meaning as a noun: one of a pair of propositions so related that exactly one is true and the other false. Derived from the Latin contradicere, 'to speak against', the adjective entered English usage in the early modern period alongside its relatives contradict and contradiction. Its precision makes it valuable whenever mere difference or disagreement needs to be distinguished from outright logical incompatibility.
Mutually opposed or inconsistent, so that the things described cannot both be true, valid, or held at once.
"The study produced contradictory findings across its two trials."
Often used attributively with abstract nouns such as statements, evidence, signals, or advice.
(Logic) Either of two propositions so related that one is the negation of the other, meaning exactly one must be true and the other false.
"'All swans are white' and 'some swans are not white' are contradictories."
A technical term in traditional logic, distinct from 'contraries', where both propositions may be false.
In formal logic, a 'contradictory' isn't just a squabbling pair of claims — it's a duo so opposed that one must be true precisely when the other is false.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of contradictory
Contradictory derives from Latin contra ('against') combined with dicere ('to speak'), via the verb contradicere, 'to speak against'. The related verb contradict entered English from Latin through French in the Middle English period, and the adjective contradictory was formed on the same stem, becoming established by the early 17th century. It shares this root with other words built on dicere, such as dictate, predict, and verdict, which all involve speaking, saying, or pronouncing in some form.
Related word forms
How contradictory is actually used
Primarily formal to neutral in register; common in journalism, law, science, and logic. When applied to a person's behaviour it often carries a mildly critical connotation of inconsistency or hypocrisy.
Easily confused with contradictory
Contrary things are simply opposed or opposite, while contradictory things are mutually exclusive so that both cannot be true at once.
Contradiction is the noun for the act or instance of asserting the opposite, whereas contradictory is primarily an adjective describing things that conflict with each other.