歇后语，台语称为孽仔话（台罗：gia̍t-á-uē）或孽谲仔话（台罗：gia̍t-khiat-á-uē）是将一句话分成两部分来表达某个含义。前一部分是隐喻或比喻，后一部分是意义的解释。一部分是“俏皮话”，也可以看成是汉语的文本游戏。

最初的歇后语与现在我们看到的歇后语的表现形式并不相同，是对当时通用的成语、成句的省略。陈望道在《修辞学发凡》中称之为“藏词”。例如用“倚伏”代替“祸福”（出自《道德经》——“祸兮福所倚，福兮祸所伏。”）这种歇后语需要一定的文言功底，其使用范围受到了限制。

后来的歇后语在结构上是“比喻——说明”式的俏皮话。使用的人往往只说出比喻部分，后面的解释部分则让对方自己领悟。

Xiehouyu (simplified Chinese:歇后语; traditional Chinese:歇後語; pinyin:xiēhòuyǔ; Wade–Giles:hsieh-hou-yü; literally: "a saying with the latter-part suspended") is a kind of Chinese proverb consisting of two elements: the former segment presents a novel scenario while the latter provides the rationale thereof. One would often only state the first part, expecting the listener to know the second. Compare English "a stitch in time (saves nine)" or "a bird in the hand (is worth two in the bush)".