"Machs" is a slang term that is commonly used to describe someone who is cool, confident, and in control. There are several synonyms for this term, which include "smooth," "suave," "confident," "polished," "slick," "charming," "cool-headed," "composed," "self-assured," and "unflappable." These words are often used to describe people who exude a sense of calm and collectedness in high-pressure situations and who are able to handle any challenge that comes their way with ease. Whether referring to a person's personality or their actions, these synonyms for "machs" all convey a sense of coolness, calmness, and confidence, making them ideal replacements for the slang term.