This is the 15049th most frequent Russian word.
пожелтевший
"Пожелтевший" means "yellowed" or "having turned yellow."
The word 'пожелтевший' describes the state of the trees having turned yellow due to season change.
Осенью деревья становятся пожелтевшими.
In autumn, the trees become yellowed.
Here, 'пожелтевший' refers to a book that has changed color—yellowed—due to prolonged exposure to sunlight.
Пролежав долгое время на солнце, книга оказалась пожелтевшей.
After a long time spent in the sun, the book turned yellowed.
In this context, 'пожелтевшая' is used to describe grass that has lost its green freshness, becoming yellow due to environmental conditions like a drought.