This is the 5785th most frequent Russian word.
прохожим
"Прохожим" means "to a passerby" or "for a passerby" in English.
In this sentence, "прохожим" is the dative plural form of "прохожий," which refers to people passing by or pedestrians.
Я представил себе, как прохожим нравится этот парк.
I imagined how the passersby enjoy this park.
Here, "прохожим" is also in the dative plural form, used because the passerby are the recipients of assistance (indirect object).
Мы помогли прохожим найти нужный путь.
We helped the passerby find the right path.
In this example, "прохожих" is the accusative plural form of "прохожий," indicating that the passerby are the direct objects of the verb.