Tautology is the use of different words to say the same thing twice in the same statement. 'The money should be adequate enough' is an example of tautology.
英英词典释义
Noun
1. (logic) a statement that is necessarily true;
"the statement `he is brave or he is not brave' is a tautology"
2. useless repetition;
"to say that something is `adequate enough' is a tautology"