The word "好友" is formed by combining two independent characters, each carrying its own core meaning, to create a new, unified concept. The first character, "好" (hǎo), fundamentally means "good" or "well", conveying a sense of positive quality and harmony. The second character, "友" (yǒu), means "friend" or "friendship", denoting a bond between people. Their formation into "好友" is a conceptual fusion where "good" directly modifies "friend", thus semantically specifying and elevating the type of friend to one characterized by closeness, affinity, and positive regard, effectively meaning "a good friend".