Forever and Unfading

Forever adverb - For all time.

Unfading and forever are semantically related In some cases you can use "Unfading" instead an adjective "Forever".

Unfading adjective - Of an imaginary flower that never fades.

Forever and unfading are semantically related in endless topic. Sometimes you can use "Forever" instead an adjective "Unfading", if it concerns topics such as constant, eternal.