Question

Why is the season of mists called the 'close bosom-friend 'of the sun​

Answer 1

Answer:

Season of mists and mellow fruitfulness, Close bosom-friend of the maturing sun; From the title it's clear that the speaker is talking about autumn. The speaker briefly describes the season and immediately jumps into personification, suggesting that autumn and the sun are old pals

Autumn is a close friend of the sun, who is "maturing" as the year goes on. "Maturing" could be a polite way of saying "getting old." The sun is no longer in its prime. A "bosom-friend" is like that friend you told all your secrets to in junior high school.