Obstacle is the opposite of Benefit. Benefit is related to Reward. Reward is related to Recognition. 
Accurate is a synonym of Perfect. Perfect is related to Absolute. Absolute is similar to Living. Living can be Hard. 
Obstacle <--Antonym--> Benefit <--RelatedTo--> Reward <--RelatedTo--> Recognition 
Accurate <--Synonym--> Perfect <--RelatedTo--> Absolute <--SimilarTo--> Living --HasProperty--> Hard 