Hostile is similar to Aggressive. Aggressive is similar to Competitive. Competitive is the opposite of Cooperative. 
Ceo is related to Executive. Executive is related to Organization. Organization is related to Big. 
Hostile <--SimilarTo--> Aggressive <--SimilarTo--> Competitive <--Antonym--> Cooperative 
Ceo <--RelatedTo--> Executive <--RelatedTo--> Organization <--RelatedTo--> Big 