There are various synonyms for the word "luck in", which means to have good fortune or to be successful. Some similar terms include "succeeding", "prospering", "thriving", "flourishing", "triumphing", "prevailing", "scoring", and "achieving". These words all connote the idea of achieving one's goals through some stroke of good luck or fortune. The connotation of these synonyms is generally positive and implies success, usually in a financial or career-related context. Whether you say "luck in," "succeed," or "prosper," the implication remains the same: things are going well and you are achieving your desired outcomes.