Taken from the abbreviation of Alex Rodriguez, a former Seattle Mariners baseball player who signed to the Texas Rangers for what was then considered the highest wage (approx. $25 million) in American Baseball. Later, he resigned to the New York Yankees.
Sometimes A-Rod is seen as a positive distinction for someone who is popular and likable, possibly even affluent and sought after. However, in most places (i.e., Washington State, Texas) being called an A-Rod is considered an insult, meaning “sell-out” or even as a derogatory term for someone who is sexually easy, male or female. The term can be used to describe others in the media, sports, or television, or known acquaintances.
Can be used as an adjective, sometimes a noun.
"Man, Good Charlotte has gone so A-Rod."
"Pay Mary Jane enough and she'll go A-Rod for ya."
"Man, Justin is such an A-Rod."