expression, noun-modifying (irregular)
Describes a friend, colleague, or companion with whom one can be completely at ease, sharing true feelings without pretense. Used prenominally (before a noun).
He is a trusted friend I can be myself with.
Traveling with close companions who know you well is fun.
A fixed expression combining 気心 (one's true feelings and nature) and 知れた (the perfective form of 知れる, 'to be known'). Literally 'one's heart and mind are known', it describes a relationship of deep mutual understanding.