A person who protects, watches over, or is legally responsible for someone or something. Often used in formal, legal, or fantasy contexts.
He became the legal guardian of his younger brother.
The custodian of the temple offers prayers every day.
Compound of 守護 (shugo, 'protection') + 者 (sha, 'person'). The exact historical derivation is uncertain, but the kanji composition directly reflects the meaning.