a person who believes that nothing is known or can be known of the existence or nature of God.
adjective
relating to agnostics or agnosticism.
(in a non-religious context) having a doubtful or non-committal attitude towards something:until now I’ve been fairly agnostic about electoral reform
[usually in combination] Computing denoting or relating to hardware or software that is compatible with many types of platform or operating system:many common file formats (JPEG, MP3, etc.) are platform-agnostic