Busy is a synonym of Active. Active is related to Live. Live requires Retire. Retirement is derived from Retire. 
Drawer is related to Sock. Sock is related to Single. 
Busy <--Synonym--> Active <--RelatedTo--> Live --HasPrerequisite--> Retire <--DerivedFrom-- Retirement 
Drawer <--RelatedTo--> Sock <--RelatedTo--> Single 