also: なにびとたりとも · なんびとたりとも
expression
no one at all; nobody, whoever they may be
Emphatic expression meaning 'absolutely no one', used in formal or written contexts. Often followed by a negative predicate.
何人たりとも、この部屋に入ることは許されない。
No one at all is permitted to enter this room.
何人たりとも、法の上では平等である。
Everyone, without exception, is equal under the law.
誰も is the common, neutral way to say 'no one' or 'anyone' in negative sentences. 何人たりとも is more emphatic and formal, stressing that there are absolutely no exceptions.
Compound of 何人 (nanpito/nanibito, 'any person') + たりとも (tari to mo, classical emphatic particle combination meaning 'even if one is'). The phrase literally means 'even if one is someone', i.e., 'no matter who'.