This is the 16629th most frequent Turkish word.
yorucu
Tiring.
The word 'yorucu' is used here as an adjective to describe the activity (long walk) as exhausting, emphasizing its tiring nature.
Bu uzun yürüyüş gerçekten çok yorucuydu.
This long walk was really very exhausting.
In this instance, 'yorucu' is part of a noun clause (exhausting day) that characterizes the day as being tiring or draining.
Yorucu bir günün ardından dinlenmeye ihtiyacım var.
After an exhausting day, I need to rest.
Here, 'yorucu' is used to describe an abstract concept (arguing with people) as something that can be tiresome or wearying.