Slight is the opposite of Significant. Significant is a synonym of Massive. Massive is similar to Solid. Solid is similar to Serious. 
Cross is a type of Fold. Fold is a synonym of Yield. Yield is a synonym of Product. Product is related to Smoke. 
Slight <--Antonym--> Significant <--Synonym--> Massive <--SimilarTo--> Solid <--SimilarTo--> Serious 
Cross --IsA--> Fold <--Synonym--> Yield <--Synonym--> Product <--RelatedTo--> Smoke 