Question

Lethargic : vital :: trite :

Answer 1

Lethargic means "sluggish", kind of inactive
Vital means full of energy, lively

So, they are antonyms

So, for the 2nd part of the analogy, you are looking for a antonym to trite

Trite means lacking originality or freshness. Overused. Kind of like a cliche

So, an antonym could be original, unique, innovative