Fromkin's Introduction to Linguistics says:
Language purists sometimes rail against back-formations and cite enthuse and liaise [from enthusiasm and liaison) as examples of language corruption. However, language is not corrupt; it is adaptable and changeable. Don’t be surprised to discover in your lifetime that shevelled and chalant have infiltrated the English language (from disheveled and nonchalant) to mean “tidy” and “concerned,” and if it happens do not cry “havoc” and let slip the dogs of prescriptivism; all will be well.
What does "the dogs of prescriptivism" mean?