Whimsical : Monotonous1)  Lethargic : Spirited2)  Healthy : Robust3)  Imply : Conclude4)  Replay : Highligh

"Whimsical : Monotonous" - These are antonyms. Whimsical means unpredictable or having a lot of ideas, while monotonous means dull or repetitive.

"Lethargic : Spirited" - These are also antonyms. Lethargic means lacking energy or enthusiasm, while spirited means full of energy or enthusiasm.

"Healthy : Robust" - These are synonyms. Both healthy and robust mean strong and in good health.

"Imply : Conclude" - These are related but not exactly the same. To imply means to suggest something without saying it directly, while to conclude means to decide something after considering all the information.

"Replay : Highlight" - These are related in the context of media. A replay is a repeat of a play or event, often in sports, while a highlight is a particularly good or exciting part of something, such as a game or show.