1. having the greatest physical weight or mass
Usage: superlative form of weighty
2. most important, serious, or significant
Usage: superlative form of weighty

Examples

• The weightiest box required two people to lift it.
• She saved the weightiest decision for last.
• The committee discussed the weightiest issues first.
• This is the weightiest responsibility I’ve ever had.
• The weightiest evidence supported their theory.
• He carried the weightiest burden of all the team members.