Clean is similar to Easy. Easy is related to Gentle. 
Play is related to Trouble. Trouble is related to Disaster. Disaster is related to Relief. Relief is etymologically related to Relieve. 
Clean <--SimilarTo--> Easy <--RelatedTo--> Gentle 
Play <--RelatedTo--> Trouble <--RelatedTo--> Disaster <--RelatedTo--> Relief --EtymologicallyRelatedTo--> Relieve 