Wordology, Egg Someone On

This is one of those idioms where you think the etymology would be obvious, but this phrase has nothing to do with eggs.

The egg in this expression is a verb meaning “to goad” or “to incite” which is derived from the Old Germanic dialect word, eggia. The word is related to the Old English word, ecg, meaning “an edge.” It is also related to the Middle Low German eggen, meaning “to harrow.” Therefore, this may suggest that someone is “egged” on in fear of being prodded with something sharp, but this is only a vaguely implied connection.

The word came into English around the year 1200, originally in the sense of provoking or tempting a person. Today, the phrase means to encourage someone to do something, usually of a risky, foolish, or dangerous nature. In other words, people egg one another on to get a reaction.