The point of one's attraction to another person is so overwhelming or all-consuming, they start acting like a retard. (Usually at least one degree past twitterpated.)
A word used to express distaste toward something or some action that was not expected or not appropriate. It comes from the word Retarded but is used more as an association to an action or a state of being.
"Dude, that is retardimacated..." or "That was a retardimacated thingto do..."