Whimsicott

Whimsicott => is Pokemon dex #547 (regular rare Pokemon)

Opendex
=> Pokemon you already have/registered in your Pokedex, displayed as images and Pokemon details

Non-Opendex
=> Pokemon you don't have yet/not registered in your Pokedex, shown as a black shadow (meaning you've seen it in raids/gyms) or just the Pokedex number

Trade Requirements for Opendex:
1. Must have 100 Stardust
2. Must have the Pokemon registered in your Pokedex

Trade Requirements for Non-Opendex:
1. Must have 20,000 (20K) Stardust
2. The Pokemon is still a shadow or you don't own it yet

Note: Tip for Non-Opendex (Legendary Pokemon/Shiny Pokemon) – Be willing to level up friendship to Ultra Friends to reduce Stardust cost (80,000 Stardust). If you're willing, buy the cheapest or your favorite Opendex Pokemon from Wantau Store, then message the seller to request a 30-day friendship (Ultra Friend).

How to Trade Opendex or Non-Opendex? Check the link below: