Worry is related to Anxiety. Anxiety is related to Worried. Worried is related to Fear. Stranger can be used for Fear. 
Imagine is a synonym of Suspect. Suspect is related to Guy. 
Worry <--RelatedTo--> Anxiety <--RelatedTo--> Worried <--RelatedTo--> Fear <--UsedFor-- Stranger 
Imagine <--Synonym--> Suspect <--RelatedTo--> Guy 