Quit is a synonym of Depart. Depart is a synonym of Abandon. Abandon is a synonym of Yield. 
Reduce is a synonym of Limit. Limit is related to Amount. Amount is related to Portion. 
Quit <--Synonym--> Depart <--Synonym--> Abandon <--Synonym--> Yield 
Reduce <--Synonym--> Limit <--RelatedTo--> Amount <--RelatedTo--> Portion 