Here , fair means, the right road, a better and wiser option among the two.

The word "fair" in the poem "The Road Not Taken" refers to the appearance of the two paths that the speaker has to choose from. The speaker describes the paths as "just as fair" meaning that both paths look equally appealing and attractive.

The Fair Appearance of the Paths
The speaker is faced with a fork in the road and has to choose which path to take. The speaker describes the paths as "yellow wood" and says that both paths "equally lay" meaning that they both have the same starting point. He then goes on to say that both paths look "just as fair" meaning that they both look equally attractive and appealing.

The Choice
The speaker has to make a choice and decides to take the less traveled path because he wants to be different and take a path that is not as popular. He says that he will come back and take the other path another day, but he knows that he probably will not because he realizes that once a choice is made, there is no going back.

The Meaning
The poem is about the choices we make in life and how they shape our future. The speaker is faced with a choice and decides to take the road less traveled, which has made all the difference in his life. The word "fair" in the poem refers to the appearance of the paths, but it also has a deeper meaning. The speaker is saying that both paths look equally good, but he has to make a choice and take a chance on one of them.