This is the 16041st most frequent Russian word.
пьяного
"Пьяного" means "drunk" or "intoxicated" in English.
In this sentence, 'пьяного' is an adjective in the accusative case that describes 'человека' (man), indicating that the man is inebriated.
Я увидел однажды пьяного человека, который пытался найти дорогу домой.
I once saw a drunk person trying to find his way home.
Here, 'пьяного' is used in the genitive case as part of the phrase 'о пьяного прохожем', emphasizing the quality of the passerby being drunk.
Они говорят о пьяного прохожем, что удивляет их своими поступками.
They are talking about a drunk passerby surprising them with his actions.
'Пьяного' functions as an attributive modifier in the genitive case describing 'мужчины' (man), used to denote the property of being intoxicated.