哥俩 = 哥儿俩, a colloquial fusion meaning "the pair of brothers/buddies." Use with 们 for the group: 他们哥俩. Female equivalent is 姐俩 (jiěliǎ); generic mixed pair is 俩 (liǎ) alone.
register
Casual / spoken. Carries warmth — implies real closeness, whether literal brothers or chosen-family male friends.
