Habit is related to Manner. Manner is related to Discipline. Discipline is related to Strict. Strict is a synonym of Harsh. 
Past is similar to Last. Last is a synonym of Persist. Persist is a synonym of Remain. 
Habit <--RelatedTo--> Manner <--RelatedTo--> Discipline <--RelatedTo--> Strict <--Synonym--> Harsh 
Past <--SimilarTo--> Last <--Synonym--> Persist <--Synonym--> Remain 