A graybeard is an idiom way used in the English language to describe someone who is significantly old. Depending on the context of this slang expression, it may have either a positive or a negative connotation attached to it when it used. In some cases, calling someone a "graybeard" may bestow on them a distinguished aura and imply the wisdom that is supposed to accompany old age. There are also times when the way this idiom is used suggests that someone is so old that he or she can no longer be very effective in society.
In the English language, there are often many different ways available to say one particular thing. Using idioms and slang allows a person to add some color and impact to his or her speech. It also allows for communication between people who are aware of what these expressions mean, creating a kind of conversational shorthand. Many different idioms and slang words have arisen to describe people of advanced years, and one of the most familiar of these terms is the idiom "graybeard."
When someone is described in this manner, the implication is that he or she is relatively old compared to the average person. The context in which it is used determines whether it is a loving term or a derisive one. Many people associate old age with wisdom. Those people are more likely to use this term in a positive manner. Consider the sentence, "That old graybeard has sure seen a lot of amazing things in his lifetime."
On the other hand, there are those who associate the time at the end of one's life with confusion and uselessness. These are the people who will likely use this term in ways that make it sound like an insult. For example, someone might ask, "How can we expect that graybeard to fix our car when he can barely walk?" In this case, old age is considered to be more of a hindrance than a help.
This idiom gets its meaning from the fact that it is not uncommon for older men to actually have gray beards. Calling someone a "graybeard," however, might not mean that he or she literally has a gray beard. In fact, a group of old people might be called "graybeards," even if some members of the group are women. The phrase is not meant to be taken literally. It simply suggests old age to anyone who hears it.