1. no belief
2. no knowledge
3. no idea

1. Atheist - Do not believe in any gods whatsoever.

2. Agnostic - Don't know one way or the other.

3. Spiritual - Need some woo to hang onto, but don't want religion.

1 lack of theism
2 lack of absolute knowledge
(Important to remember 1 and 2 are not mutually exclusive. Both apply to most rational people)

3 lack of critical thinking, or a nebulous offramp for religion until you realize you're an agnostic atheist.

1. Atheist Someone who has insufficient evidence to justify the reality of a god or gods
2. Agnostic An Atheist with out the courage of their convictions
3. Spiritual In the context of this discussion a hypocrite

Asked and answered a hundred times on here.
The great thing about words is that they have concrete definitions.
Therefore, it doesn't matter what someone's "personal definition" is because there is, and always will be, a real definition.
Google is your friend if you are looking for definitions.

1. Lacks belief in the claim that deities exist.

2. Does not know that it is impossible for deities to exist

3. Stuff and nonesense that people use to fudge emotions they cannot explain.

I like Matt Dillhanty (spelling?) definition. Atheist is a lack of belief in a god as there as never been any proof of the existence of a god.
Agnostic is much the same. The word gnostic means knowledge and agnostic means the lack of knowledge of a god or gods.
Spiritual is harder to define as that is a personal experience. For me it is wonder, awe, joy I feel when I contemplate the Cosmos.

Labels

Atheist: does not believe in god(s).

Agnostic: undecided about existence of god(s).

Spiritual: senses a connection to all things living and nonliving.

1. Someone who rejects the claims of the existence of a god or gods because they haven’t met their burden of proof and is eagerly willing to change their mind.

2. Someone who holds the position of “we don’t know whether a god exists or not.”

3. I have no clue. I know atheists/ agnostics that saythey are spiritual. But I don’t get it....like meditation and yoga? I don’t think they actually believe in spirits or souls.

Atheist - are sure there is no God

Agnostic - it's not possible to know if there is a God or not

Spiritual - don't necessarily believe in the traditional sense of a God (although some do), but believe in a supernatural energy or essence in humans. An intangible like a soul.

1. Don't believe in god(s) as there is no proof

2. Don't care

3. Don't care

Atheist - Positive that gods and religions are bullshit made up by humans
Agnostic - Not sure if gods and religion are bullshit made up by humans
Spiritual - Leaning that gods and religion are bullshit, but want "something" to be there.

1. One who has no beliefs concerning deities.
2. One who sees knowledge of god as unobtainable.
3. Whatever unctuous bullshit one wishes to spout.

1. someone who believes there are no gods, or fails to believe there are any gods.
2. someone who fails to believe there are any gods, or isn't sure whether there are any gods but leans toward there not being any
3. religion light

g

An atheist is someone who does not accept the god or God claims. They could completely say they do not believe in God or gods.

An agnostic does not know if there is a God or gods.

Spiritual I have absolutely no idea what that is supposed to mean.

Atheist say there is no God (which is a belief because they they don't really know that). Agnostic says they just don't know (which is the correct choice). Spiritual means increasing one's feeling of self awareness while we are here on a search for meaning in our lives. Trying to be spiritual is a noble undertaking.
However we should be careful not to equate spiritual with "soul" because more than likely the is no such thing as a soul.

Atheism and agnosticism are pretty straight forward but spirituality is far more ambiguous. I believe I'm spiritual because I can be so emotionally moved by things (real things that is) For example, I can be brought to tears when I hear a choir sing Handel's messiah. I'm certainly not religious but it is an amazing piece of work. The exuberance of standing on a precipice, looking down on the vast valley bellow. The thrill of riding my motorbike far too fast, weaving in out of city traffic. THe awe of looking at the vastness of stars as I reflect on how insignificant I am in comparison to the universe. When I create something beautiful and original, it is like an extension of me. When I connect with someone who is a stranger and we realise we are so like-minded. I believe in the interconnectedness of humans and all living things and that no one should be alone because we need each other to thrive. I see the beauty and the pain and this to me is a spiritual experience.

I agree with 'scrunchy'...labels.

Atheist - not believing in any god(s)
Agnostic - Uncertain of the existence of a god/higher power
Spiritual - probably leans agnostic but believes in an ethereal soul/aura/energy in living things. Some will include plants and animals aside from humans...some will include humans only

1. Someone who does not believe in gods.
2. Someone who acknowledges that there is no evidence gain knowledge about gods.
3. Someone who is honest enough make up their own beliefs instead of becoming a cherry-picker while still calling themselves a Christian/Muslim/Jewish etc.

1. believing in zero
2. without knowledge of any
3. believing in something unproven

Intelligence!!!

Atheist: I believe there is no supernatural.
Agnostic: Knowing that I can not prove the none existence of something outside of reality, even if I'm sure its bull.
Spiritual: Smoke-screen used by some to hide their belief in things outside of reality.