Take a look at the adjective “timorous” and you can likely guess an almost-exact synonym: “timid.” Both come from the Latin verb “timere,” meaning “to fear,” but “timorous” was in use in late Middle English, around the mid-15th century, while “timid” didn’t enter English until the mid-16th century. While they are extremely close in meaning, there is a slight difference in usage. “Timorous” is best used when the nervousness is due to a fearfulness, while “timid” is the adjective for when shyness is in play.