Stoicel is a blend of the words "stoicism" and "incel". A stoicel is someone who has gotten so used to their inceldom that it no longer bothers them. This is called taking the whitepill. Stoicels may have reached this point through gradual conditioning or because they already had ascetic elements to their personality.
Stoicels are knows as "Solitude Titans" in the Russian incelosphere.