Slight is the opposite of Important. Important is the opposite of Light. Light is the opposite of Crucial. Crucial is a synonym of Significant. 
Butterfly is related to Swim. Swim is related to Dancing. Dancing is related to Move. 
Slight <--Antonym--> Important <--Antonym--> Light <--Antonym--> Crucial <--Synonym--> Significant 
Butterfly <--RelatedTo--> Swim <--RelatedTo--> Dancing <--RelatedTo--> Move 