Register is a synonym of Enroll. Enroll is a synonym of Add. Add is related to Put. 
Complicated is a different concept from Easy. Easy is etymologically related to Ease. Ease is a synonym of Cruise. Cruise is a type of Search. 
Register <--Synonym--> Enroll <--Synonym--> Add <--RelatedTo--> Put 
Complicated <--DistinctFrom--> Easy --EtymologicallyRelatedTo--> Ease <--Synonym--> Cruise --IsA--> Search 