Four of the following five are alike in a certain way so form a group. Which is the one that does not belong to that group? 

In the following question, select the related word from the given alternatives.
Encouragement: Victory :: Frustration: ?

Select the odd word from the given alternative

In the following question, select the related number from the given alternatives.
243: 819 :: 163 :?

In the following question, select the related word from the given alternatives.
Triangle: Hexagon:: ?

In the following question, select the related word from the given alternatives.
Spring: Summer :: ?