Both words can refer to a sudden spell of heightened emotion or activity, which for both words is an extension of a medical definition for a sudden attack or intensification of a disease. Paroxysm conveys a violent, serious spell of emotion or activity more consistently than fit, but both words are used of strong emotions: a fit of rage; paroxysms of anger, rage, laughter, grief. Fit can also be applied (without facetiousness) to the onset of less acute, intense states: a fit of inactivity; a fit of nostalgia. When eruptions of emotion and activity are attributed to whole populations or geopolitical entities, paroxysm is much more likely to be used: global paroxysms; a paroxysm of nationalism.

Flashy and gaudy describe things that are conspicuously showy and intended to attract attention and impress. Flashy suggests a person’s blatant, glitzy display of wealth (real or apparent): flashy cars; flashy clothes. Gaudy is less about personal lifestyle and consumption and more about taste and aesthetics. Gaudy suggests excessively bright colors and ornamentation, often tasteless or cheap: gaudy Christmas lights; gaudy gold ring; gaudy colors; gaudy costume.

In casual use, especially when the topic is Halloween or horror movies, ghastly and ghoulish get lumped together, along with other grisly, gory, and gruesome words beginning with the letter “g.” Ghastly and ghoulish have the definitions “like a ghost” and “like a ghoul,” but it’s the extended meanings we’re concerned with here. Ghastly, often used of acts and events, suggests something shockingly frightful, horrible, or repellent, particularly to the eye. You can be sure a ghastly accident or ghastly murder involved a fair amount of blood and gore. Ghoulish is less frequent, as ghouls are less prominent in American culture than ghosts. A ghoul is a demon originating in Muslim lore, said to dig up graves and feed on human corpses, and ghoulish suggests something that demonstrates monstrous cruelty or a fascination with such: the zombies’ ghoulish mission; ghoulish fascination with serial killer movies.