ichidan verb
be punished; be subject to punishment
Irregular passive form of 罰する (to punish). Used when someone receives punishment, often in formal or legal contexts.
法律に違反すると罰せられる。
If you violate the law, you will be punished.
彼はその罪で厳しく罰せられた。
He was severely punished for that crime.
罰する is the active transitive verb 'to punish'; 罰せられる is its irregular passive form meaning 'to be punished'.
Irregular passive form of 罰する (ばっする). The expected regular passive would be 罰される (ばっされる), but 罰せられる is the standard form.