A play on words, also known as a homophone, involving the name Juan and the word 'one' or any other word which creates the 'wha' sound, i.e. one=Juan.
Juanisms are a common occurrence in the United States. However, due to the less frequent occurrence of the name Juan, Juanisms are particularly entertaining in English speaking countries where the Latino population is significantly lower. ex. Canada
Examples of Juanism(s);
juanderful, juan on juan, buy juan get juan free, two for the price of juan, the Juan and only, juant not waste not,...you get the idea.