weightiest
Adjective
The word is derived from weighty
Examples
Man must not only make himself: the weightiest thing he has to do is to determine what he is going to be. He is causa sui to the second power.
In the weightiest matters we must go to school to the animals, and learn spinning and weaving from the spider, building from the swallow, singing from the birds,-from the swan and the nightingale, imitating their art.
The weightiest end of the cross of Christ that is laid upon you, lieth upon your strong Savior.