Definition from Wiktionary, the free dictionary
- (uncountable) The policies of U.S. president John Tyler.
- The practice of abandoning the political party to which political office is owed, defecting while in office, committing political apostasy.
Related terms 
- 1842, The Foreign Quarterly Review
- The last resort of Tylerism is not only destined to be a signal failure, but those who pretend to be Mr. Tyler's friends, and have some little knowledge of the people, will tell him that it was conceived in folly and madness; and that it will not secure him an additional supporter among the people.
- 1845, The American Review
- The defunct carcass of Tylerism bred a political pestilence, congenial to the vitality of Locofocoism, and it throve upon it—fatal to healthier organs, and we were enfeebled by the malaria.
- 1845, The United States Democratic Review
- For even though the hour has not yet quite arrived, which is to be brightened by the reflection that Tylerism has ceased to exist, in any other than the past tense, yet, by the time this page shall reach the eyes of most of its readers, they will have ceased to blush for the government of their country.