A truism is a statement that is generally accepted as obviously true and is repeated so often that it has become boring.
例句
Orpington seems an example of the truism that nothing succeeds like success...奧爾平頓似乎驗證了一個常理——一事成功百事順。Whilst this might sound like a truism, it is nevertheless a crucial problem to address.盡管這可能聽起來像是老生常談，但卻是待解決的重要問題。
英漢詞典釋義
n.
自明之理, 老生常談
It is an obvious truism that people act in accordance with their motives.人人都按自己的動機行事是不言而喻的。