ダチ公こうMeanings1nounbuddy; pal; friendslang›dated termDated slang term for a close male friend, often used among young men. The 公 suffix adds a rough, familiar, or slightly derogatory tone. Comparable to 'dude' or 'bro' in English.See also: ダチあいつは俺おれのダチ公こうだ。That guy's my buddy.ダチ公こうとつるんで遊あそびに行いった。