Practical is a synonym of Virtual. Virtual is the opposite of Legal. Legal is related to Limit. Limit is related to Regulation. 
Contract is related to Business. Card can be used for Business. Card is related to Pack. 
Practical <--Synonym--> Virtual <--Antonym--> Legal <--RelatedTo--> Limit <--RelatedTo--> Regulation 
Contract <--RelatedTo--> Business <--UsedFor-- Card <--RelatedTo--> Pack 