An English Oppositional Collocation refers to a special expression combined of a commendatory adjective and a derogatory adverb, resulting in a highly positive meaning, such as dead good, terribly glad and so on. Through the collection of relevant corpus, we find that some English taboo words can be used as a degree adverb in oppositional collocations. They are damn, bloody, fucking and dead. Research shows that the reason why taboo words can be used in the oppositional collocation is that they themselves have undergone grammaticalization. Its motivation is related to human’s cognitive psychology and pragmatic factors, and its mechanism includes metaphor, metonymy and subjectification.