在14世纪中期，“相对的、对立的、在对面或相反方向的；极不相似的、最不相似的”这个意思源自盎格鲁-法语的 contrarie 和古法语的 contrarie，直接来自拉丁语的 contrarius，意为“相对的、对立的；相反的、逆向的”，其中 contra 意为“反对”（参见 contra）。到了14世纪晚期，这个词还引申出了“喜欢反驳的、任性的、难以对付的”意思；而“有害的、不利的”则也是在14世纪晚期出现的。相关词汇还有 Contrarily。
作为名词使用始于13世纪晚期，指“一对字符、命题、术语等中，属于同一类别但最不同的那一对”。短语 on the contrary（“与所说的恰恰相反”）大约在1400年就有记录，当时写作 in the contrary。
If we take the statement All men are mortal, its contrary is Not all men are mortal, its converse is All mortal beings are men, & its opposite is No men are mortal. The contrary, however, does not exclude the opposite, but includes it as its most extreme form. Thus This is white has only one opposite, This is black, but many contraries, as This is not white, This is coloured, This is dirty, This is black; & whether the last form is called the contrary, or more emphatically the opposite, is usually indifferent. But to apply the opposite to a mere contrary (e.g. to I did not hit him in relation to I hit him, which has no opposite), or to the converse (e.g. to He hit me in relation to I hit him, to which it is neither contrary nor opposite), is a looseness that may easily result in misunderstanding; the temptation to go wrong is intelligible when it is remembered that with certain types of sentence ( A exceeds B) the converse & the opposite are identical ( B exceeds A). [Fowler]
例如，假设我们有命题 All men are mortal（“所有人都是凡人”），那么它的对立命题是 Not all men are mortal（“并非所有人都是凡人”），而它的逆命题则是 All mortal beings are men（“所有凡人都是人”），它的相反命题则是 No men are mortal（“没有人是凡人”）。不过，对立命题并不排除相反命题，反而将其视为最极端的形式。因此，命题 This is white（“这是白色的”）只有一个相反命题， This is black（“这是黑色的”），但却有许多对立命题，比如 This is not white, This is coloured, This is dirty, This is black（“这不是白色的，这有颜色，这很脏，这这是黑色的”）；至于最后一个形式是被称为 contrary（对立命题），还是更强调地称为 opposite（相反命题），通常并没有太大区别。然而，如果将 the opposite（相反命题）错误地应用于仅仅是对立命题（例如，将 I did not hit him（“我没有打他”）与 I hit him（“我打了他”）进行比较，因为后者并没有相反命题），或者将其应用于逆命题（例如，将 He hit me（“他打了我”）与 I hit him（“我打了他”）进行比较，因为这两者既不是对立命题也不是相反命题），那么这种用法的松散性可能会导致误解；这种错误的诱惑在某些句型中是可以理解的，比如 A exceeds B（“A超过B”），因为在这些情况下，逆命题和相反命题是相同的（B exceeds A（“B超过A”））。[Fowler]
