adjective
BAD : The man was obviously drunken.
GOOD : The man was obviously drunk.
BAD : One of the two drunken men shouted at me.
GOOD : One of the two drunks shouted at me.
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Drunken is rarely used to describe a person. It usually describes an action or event: 'drunken driving', 'drunken laughter', 'a drunken brawl', 'a drunken orgy'. The exception is 'drunken drivers' (usually drunk drivers in AmE). Drunken always comes before a noun.
To describe a person, use drunk (NOT drunken ): 'I think he wanted to get us all drunk.' 'One of the students was always getting drunk.' Drunk is not used before a noun.
When you mean 'a person who is drunk', use a drunk : 'A couple of drunks were causing a disturbance.'