Spiritual is derived from Spirit. Spiritual is related to Angel. Angel is related to Dead. Dead is related to Coal. 
Coal is related to Burning. Burning is similar to Important. 
Spirit <--DerivedFrom-- Spiritual <--RelatedTo--> Angel <--RelatedTo--> Dead <--RelatedTo--> Coal 
Coal <--RelatedTo--> Burning <--SimilarTo--> Important 