合成词的形成都是人们组合现成语言材料以说明某种新的认识成果。合成词的形成比其他词的形成更加复杂 ,同时也更具有论证性 ,赋予了合成词形成的有理性。它的有理性 :一是来源于人们对造词所运用的语言材料的共识性 ,二是源于人们认识的共通性。合成词的产生也具有任意性、有理性和任意性的矛盾的统一。 The formation of compound words is the combination of off-the-shelf language materials to illustrate some new cognitive achievement. The formation of compound words is more complicated than the formation of other words, but also more assertive, giving reason for the formation of compound words. Its rationality is that one is from the consensus of language materials used by people in making poems and the other is from the commonality of people’s understanding. The synthesis of words also has the arbitrariness, rational and arbitrary unity of contradictions.