The act of treating someone as a brother, showing brotherly affection, or establishing a brother-like relationship.
From the verb 'to brother' (to treat as or become a brother) plus the progressive suffix '-ing'. While 'brother' is primarily a noun, adding '-ing' verbalizes it, a productive process in English.
English turns nearly anything into a verb—'brother' became 'to brother' became 'brothering,' showing how flexible English is compared to languages with strict rules about what parts of speech can do.
Complete word intelligence in one call. Free tier — 50 lookups/day.