Be lost and Fading away

Fading away and be lost are semantically related In some cases you can replace term "Fading away" with "Be lost", this terms are similar.

Fading away noun - Gradually diminishing in brightness or loudness or strength.

Be lost and fading away are semantically related in disappear topic. Sometimes you can use "Be lost" instead a verb "Fading away", if it concerns topics such as vanish.