When a person says a Rickism, he/she uses a figure of speech or an expression, where the essential point and meaning has been understood by the person using it, but the actual expression is said wrong because he/she never bothered to learn the actual expression- only when to use it
it originates from the series "Trailer Park Boys" where the maincharacter RICKY uses alot of these "Rickisms"
A Rickism would be:
"goddamn, it looks like an earthquake blew through here"
"by shopping there, you get two birds stoned at once"
"make like a tree, and fuck off!"