cock

The word "cock" has a long history, tracing back to Old English cocc, likely an imitative name for a male chicken. This remains its primary neutral definition: a mature rooster. From this animal's proud behavior, we get the figurative sense of a "cocky" person—someone who displays an exaggerated sense of self-importance or swagger. In older or more literary English, you may also see "cock" used for a man who sees himself as the top figure in a group (as in the phrase "cock of the walk").

In technical and mechanical contexts, the word is quite common and non-offensive. It refers to a "stopcock" or valve used to control the flow of liquid or gas. Historically, it also referred to the hammer or firing mechanism of a gun (such as a "flintlock" or "snaphaunce"). This led to the verb "to cock," meaning to pull back the hammer of a firearm or, more generally, to tilt or turn something upward or to the side, such as "cocking an eyebrow" in suspicion.

Unfortunately, the word is also commonly encountered as crude slang for the male anatomy. This specific usage is considered extremely vulgar and disrespectful. Because of this strong association, many English speakers prefer the word "rooster" for the bird and "valve" or "tap" for the mechanical part to avoid any potential misunderstanding. Understanding "cock" requires a balance of knowing its useful mechanical and behavioral meanings while being deeply sensitive to its status as a potent profanity.