(ぜい)

ぜい
suffix
the ~ crowd; the ~ contingent; group of people
informalcolloquialpersonsociety
1. the ~ crowd; the ~ group; the ~ contingent
Attaches to a noun to name the set of people who share an attribute, position, or attitude — for example 若手(わかて)(ぜい) (the younger contingent) or ガチ(ぜい) (the serious players).
The top-ranked group is strong.
The strong showing of the younger contingent stood out at this tournament.
This game has a serious crowd chasing records and a casual crowd who just play for fun.

From (せい) (force, troops), voiced to ぜい as a suffix. Originally used of military forces and sports contingents; it is now freely productive online, where new ~(ぜい) words are coined constantly.

Common examples

Register: the established combinations (上位(じょうい)(ぜい), 若手(わかて)(ぜい)) appear in sports reporting; freshly coined ones are casual internet usage.