Change refers to an instance of something becoming different than it was or being replaced by something new: a change in leadership; changes in the environment. Vicissitude refers to one of a succession of changes or alterations in the state, form, or condition of something over time. The most familiar use of vicissitude is in the plural, as in the vicissitudes of life. In this sense, the vicissitudes—of life, history, politics, fortune, love, or the market—suggests something like “the twists and turns” and “ups and downs” that characterize the course of any of these major human affairs when considered in its entirety. When we use “change” as a mass noun, as in “Change is constant,” this approaches the meaning of vicissitudes, but is more abstract and general. Vicissitudes evokes the particularity and number of the changes we weather.

Both words are used to describe intense or forcefully expressed emotions or opinions. Strong suggests felt or expressed with some degree of intensity: strong feelings; a strong objection, but strong’s wide range of application tends to dilute its precision and strength in these contexts. Vehement, which comes from a Latin word meaning “forceful” or “violent,” suggests something felt or expressed with intense passion. Vehement is not limited to a negative meaning (a vehement expression of his faith) but it does tend to be used most frequently for oppositional feelings and utterances: vehement protest, a vehement denial, vehement opposition. 

Both words refer to a state in which all movement or progress has ceased. Standstill is used of both physical motion and more complex and abstract processes: The train came to a standstill; Negotiations are at a standstill. Impasse is a strong synonym for standstill in the latter usage: Peace talks have reached an impasse. However, it’s a more specific word, which suggests not only total lack of movement but also the impossibility of there being a way out or through. Standstill is often used of business, industry, the economy, and traffic, while an impasse is usually “between” two opposing parties and used of issues and discussions (the budget impasse; a political impasse). It’s common to speak of reaching an impasse, resolving or solving the impasse, or even breaking the impasse.