What is the meaning of Contradiction?

The act of contradicting.

A statement that contradicts itself, i.e., a statement that claims that the same thing is true and that it is false at the same time and in the same senses of the terms.

A logical inconsistency among two or more elements or propositions.

A proposition that is false for all values of its propositional variables or Boolean atoms.

contradiction (clarification of this definition is needed)

Source: wiktionary.org