invitational

[in-vi-tey-shuh-nl]

adjective

noun

an event, as a sports competition or an art exhibit, restricted to those who have been invited to participate.

Origin of invitational

First recorded in 1920–25; invitation + -al¹

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

According to invitational veteran Alex Brown, of the Hot Knives Kitchen, winning is about keeping it simple.
The Art of Grilled Cheese
Isabel Wilkinson
April 22, 2011

"Just tell them it's a super-private party, invitational only," I said.
Little Brother
Cory Doctorow