An achichincle (a-chee-CHEEN-kleh) is a sidekick, a servant or a member of an entourage. It is a derogatory term. If you are the achichincle of someone, that means you’re intellectually and emotionally dependent on that person.
To make it more effective, use it along with pinche, as in vino con su pinche achichincle, which means “he came with his stupid sidekick”. A less folkloric synonym is gato (GAH-taw, lit. cat).
Probably the best known achichincle in the Spanish-speaking world is Don Quixote's: Sancho Panza.