tautology
1. [ noun ] (logic) a statement that is necessarily true
Examples:

"the statement `he is brave or he is not brave' is a tautology"

Related terms: truth logic
2. [ noun ] (rhetoric) useless repetition
Examples:

"to say that something is `adequate enough' is a tautology"

Related terms: repetitiveness
Similar spelling:   tautologic
  tautological