If you describe something as meaningful, you mean that it is serious, important, or useful in some way.
She believes these talks will be the start of a constructive and meaningful dialogue.
她相信这些谈话将会开启一次建设性的、意义重大的对话。
A meaningful look or gesture is one that is intended to express something, usually to a particular person, without anything being said.
Upon the utterance of this word, Dan and Harry exchanged a quick, meaningful look.
这个字一出口,丹和哈里马上交换了一个意味深长的眼神.