A quirk is a peculiarity of action, behavior, or personality. We usually use this term to discuss a minor, unimportant kind of oddity, e.g., Her one quirk was a habit of speaking to strangers in elevators. An idiosyncrasy is a characteristic, habit, or mannerism that is peculiar to an individual. This word emphasizes the person behind the behavior so much so that usually, when we talk about idiosyncrasies, we are talking about modes of behavior or ways of thinking that are so fundamentally associated with a particular person, they almost serve as identifying markers.

The verbs notify and apprise are close in meaning—they both deal with conveying information—but there are a few differences in how they are used. Notify is more likely to be used of information that needs to be formally addressed or acted on. The DMV might notify you that your driver's license is about to expire, for instance. Apprise, which is defined as “to give notice to” or “to advise,” is very often used to talk about keeping someone up to date on information that is of interest to them, or, in other words, keeping them in the loop. This verb appears most frequently in passive constructions, so while it’s perfectly appropriate to say “Julie apprised Joe of the matter,” you’re far more likely to encounter it in a pattern resembling this: “Joe asked Julie to keep him apprised of the matter.”

The nouns disaster and calamity both refer to adverse happenings, especially ones that are sudden and unexpected. A disaster is an event that causes great loss of life, damage, or hardship, such as a flood, airplane crash, or business failure. A calamity is a great misfortune or disaster, but this term emphasizes the grief or sorrow caused by such an event. Calamity is also used to refer to misery itself, or a state of pain and distress, as in “a year of calamity.”