on a first-name basis

Adverb

 * 1)  Having enough familiarity with another person to call them by their first name, as opposed to their surname.

Translations

 * Chinese:
 * Mandarin: 關係已經親密到直呼其名了
 * Danish:
 * Dutch:
 * Finnish:
 * French:
 * German: per Du
 * Hungarian:
 * Russian: на "ты"
 * Spanish: