This is the 11225th most frequent Polish word.
grzeje
"Heats" or "warms."
Here, "grzeje" means "heats" or "warms up" in the context of preparing something (water) through heating.
Grzeje wodę na herbatę.
She is heating the water for tea.
In this sentence, "grzeje" refers to the act of emitting heat or warmth, specifically by the sun.
Słońce grzeje cały dzień.
The sun is warming all day.
In this example, "grzeje" indicates the act of warming or heating oneself (hands) using an external heat source (the fireplace).