An incel is someone who has been rejected by all women. They are undesirable and are not intelligent enough or wealthy enough to be attractive.

Usually this person is hateful with little or no emotional intelligence. They could be self absorbed or narcissistic. They blame everyone (mostly women) but themselves for all their faults and mistakes.

Classic examples from pop culture include:

Hal Stewart (Tighten) from Megamind

The Phantom from The Phantom of the Opera

Agent 47 from the Hitman series

Squidward from SpongeBob SquarePants

Claude Frollo from the Hunchback of Notre Dame

Richard III from Shakespeare

Lord Farquaad from Shrek