esteemed friend; revered friend
A formal, literary term for a friend one deeply respects. Not used in casual conversation; may appear in classical or formal written contexts.
He is my esteemed friend, with whom I have walked the path of learning.
Compound of 畏 (い, 'awe, reverence') and 友 (ゆう, 'friend'). The exact historical derivation is uncertain, but the kanji combination suggests a friend held in respectful awe.