diabolical

1. ADJ If you describe something as diabolical, you are emphasizing that it is very bad, extreme, or unpleasant. 非常糟糕的; 极度的; 可恶的[非正式]

It was a diabolical error, a schoolboy error. 那是个糟糕透顶的错误，一个小学生才会犯的错误。

2. diabolicallyADV

...diabolically difficult clues. ...极其难解的线索。