Medium is related to Song. Song is the opposite of Silence. Silence is the opposite of Reply. Reply is related to Written. 
Idea is related to Propose. Propose is related to Event. Event is related to Appointment. Appointment is a synonym of Establishment. 
Medium <--RelatedTo--> Song <--Antonym--> Silence <--Antonym--> Reply <--RelatedTo--> Written 
Idea <--RelatedTo--> Propose <--RelatedTo--> Event <--RelatedTo--> Appointment <--Synonym--> Establishment 