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...奥尔平顿似乎验证了一个常理——一事成功百事顺。Whilst this might sound like a truism, it is nevertheless a crucial problem to address.尽管这可能听起来像是老生常谈，但却是待解决的重要问题。
英汉词典释义
n.
自明之理, 老生常谈
It is an obvious truism that people act in accordance with their motives.人人都按自己的动机行事是不言而喻的。