The nouns development and advancement both deal with change. But advancement implies great forward progression, the kind that we might associate with significant leaps in research or understanding. This term is also widely used to talk about active furtherance of something, such as a cause, belief, or undertaking. For instance, an organization might be focused on the advancement of human rights or the advancement of democratic values. Advancement may also be used to refer to promotion in rank or standing, the kind of upward movement an employee might strive for at a workplace.

To call something impeccable is to emphasize its lack of flaws, faults, or blemishes, and to suggest that it is beyond reproach. Given that criteria, it’s no surprise that impeccable also connotes rarity and—drawing on its earliest sense in English, “not liable to sin; incapable of sin”—a degree of virtuousness. An impeccable reputation, for instance, is one untainted by scandal or intrigue, and impeccable credentials are so squeaky clean, they leave no room for objection or doubt.

A desire is a longing or craving for something. An appetite is also a desire or craving, especially for food or drink. But as a synonym for desire, appetite is usually more abstract, connoting a preference, eagerness, or taste for something intangible, such as power or adventure. In these cases, appetite is usually followed by the word for to indicate the object hungered after, as in the public's appetite for change, a company's appetite for risk, or, as the case may be, a synonym seeker’s insatiable appetite for learning!