Easy is the opposite of Complex. Complex is a type of Feeling. Sensitivity is a type of Feeling. Sensitivity is a type of Sense. 
Sustain is a synonym of Hold. Jar can be used for Hold. 
Easy <--Antonym--> Complex --IsA--> Feeling <--IsA-- Sensitivity --IsA--> Sense 
Sustain <--Synonym--> Hold <--UsedFor-- Jar 