A gnostic is someone who's absolutely confirmed in their belief. An agnostic is someone who's not. It is a position on knowledge, not a position on God.
A gnostic believes that knowledge can be obtained about a given subject. An agnostic believes that knowledge can't be obtained about a given subject. A gnostic believes we can know something about a topic, an agnostic believes we can't.
It has nothing to do with certainty or conviction; it only deals with whether we can or cannot know the properties of something.
a gnostic believes that the flesh is the source of sin and denial of the flesh ( through ritual magi ck) results in salvation
and agnostic believes in God but dozen;t know which religion is true.
Agnostic thought belies an essential uncertainty about the knowable. It is about credible doubt of ontological certitude. Nothing more and nothing less. It is NOT ambivalence but rather equanimity. It values moral questions over despotic answers.
Gnosticism is a first century christian school of thought and philosophy with roots in Greek Socratic tradition. "First Know Thyself" is the motto of the Gnostic. Rather than seeking outward for answers, the gnostic seeker looks inward and to esoteric and hermetic traditions.
EDIT---and as usual Snotalie has a fortune cookie understanding of the world.