Entardecer refers to the late afternoon or dusk, the time when the day transitions into evening. It's a beautiful and somewhat poetic word that captures a specific, often reflective, moment of the day.
In the song, the lyric "Jogado num entardecer" (Thrown into a dusk/late afternoon) evokes a sense of being immersed in this tranquil time, perhaps lost in thought or simply enjoying the peaceful transition. It's more evocative than a simple "evening" and adds a touch of imagery to the lyrics.