Estimate is the opposite of Exact. Exact is a synonym of True. True is related to Correct. Correct is related to Proper. 
Fellow is related to Happy. Happy is related to Glory. Glory is related to Triumph. 
Estimate <--Antonym--> Exact <--Synonym--> True <--RelatedTo--> Correct <--RelatedTo--> Proper 
Fellow <--RelatedTo--> Happy <--RelatedTo--> Glory <--RelatedTo--> Triumph 