This is the 10123rd most frequent Russian word.
безбилетника
A person traveling without a ticket.
Here, 'безбилетник' refers to a person who tries to enter without purchasing a ticket, emphasizing the illegal or improper conduct.
Он был пойман на входе как безбилетник.
He was caught at the entrance as a stowaway.
In this case, 'безбилетники' generalizes to people avoiding paying for transport tickets, discussing the consequence of their actions.
Безбилетники часто подвергаются штрафу.
Fare dodgers are often fined.
This usage indicates individuals in a specific scenario (on a train) who travel without valid tickets.