It is a word commonly used to refer to a friend mostly towards a male, or an expression towards an illogical or horrendous situation, question, sentence, etc., it's use started around the early 20th century originating from the English word brother, used often by African American's slowly turning into 'brer' and 'brah' and now as 'bruh'.
E.g.,
Tommy: My bicycle was stolen so I had to take the subway and arrived late for class.
Charlie: Bruh.
Tommy: My bicycle was stolen so I had to take the subway and arrived late for class.
Charlie: Bruh.
by Great Floppa May 15, 2022
Get the Bruhmug. 
Something people, especially black people say instead of bro, mainly when they say in a exasperated tone.
by bootyslapper01 January 12, 2018
Get the Bruhmug. 
by AREZBETHEI September 14, 2020
Get the Bruhmug. - “are you serious...” in one word
- “you are doing something wrong but I’m too lazy to say that” in one word
- “bitch is you right” in one word
- “BOI” but weirder
- “you are doing something wrong but I’m too lazy to say that” in one word
- “bitch is you right” in one word
- “BOI” but weirder
by “RobloxDefault” May 21, 2019
Get the Bruhmug. by yourmotherWOOOOOOOOOOoooWWWW June 8, 2022
Get the Bruhmug.