Is "weary mile" a metaphorical expression? what does that mean?

Native speaker’s answer
Rebecca
Yes, it is a metaphorical expression! In the song, "weary mile" refers to the miles that he walks when he's tired and exhausted. "Weary" means tired and exhausted, and "mile" refers to a measurement of distance. Ex: We walked two weary miles from the top of the hill. Ex: The miles were weary in the summer heat.