Acquire is etymologically related to Quest. Acquire is related to Adopt. Adopt is related to Agency. Agency is related to Representative. 
Empire is related to Extension. Extension is related to Finger. Finger is the opposite of Thumb. 
Quest <--EtymologicallyRelatedTo-- Acquire <--RelatedTo--> Adopt <--RelatedTo--> Agency <--RelatedTo--> Representative 
Empire <--RelatedTo--> Extension <--RelatedTo--> Finger <--Antonym--> Thumb 