Not in my dictionary

[morning]

Hello,
I have a few statements, and hope someone can give me advice. Thanks!

1) Fail? This doesn't exist in John's dictionary.
2) You really don't know John's personality. Helping elderly? These words will never exist in his dictionary.

3) Writing a book by myself? This never exist in my dictionary.

My questions are:
a) Is this phrase 'something not in my dictionary' correct or usual way to express this particular ideas?
b) If not, would there be any common phrase or idioms that suggests the similar ideas, for statement 1 and 2?
c) Statement 3 is different from 1 and 2. In 3, it means: I want to write a book if I could, but unfortunately I don't have the skill.
Though I am not sure, I kind of feel this may not be the right way to express the original message. Can someone suggest me another way to write?

Many thanks

[BobK]

Originally Posted by morning

Hello,
I have a few statements, and hope someone can give me advice. Thanks!
1) Fail? This doesn't exist in John's dictionary.
2) You really don't know John's personality. Helping elderly? These words will never exist in his dictionary.
3) Writing a book by myself? This never exist in my dictionary.
My questions are:
a) Is this phrase 'something not in my dictionary' correct or usual way to express this particular ideas?
b) If not, would there be any common phrase or idioms that suggests the similar ideas, for statement 1 and 2?
c) Statement 3 is different from 1 and 2. In 3, it means: I want to write a book if I could, but unfortunately I don't have the skill.
Though I am not sure, I kind of feel this may not be the right way to express the original message. Can someone suggest me another way to write?
Many thanks

1 and 2 are OK - except that the normal expression is 'helping the elderly'. So the puctuation should be something like Helping? Elderly? The words will....

3 is wrong, for 2 reasons; grammar (3rd person ending), and the expression's just inappropriate. You could say

Writing a book by myself? Never in a million years.
Writing a book by myself? No chance/No hope.
Writing a book by myself? Don't hold your breath.

And if you think you could, but just don't think you will:

Writing a book by myself? That's not in my game-plan.
Writing a book by myself? That's not on the cards.

And if you're sure you could, but would never want to:

Writing a book by myself? Not [expletive of your choice] likely.

b

[morning]

Wow, thank you for your reply and for each example. I'm really glad that I asked. Everything looks so clear now. Thanks

[BobK]

Originally Posted by morning

Wow, thank you for your reply and for each example. I'm really glad that I asked. Everything looks so clear now. Thanks

My pleasure.

One last thing: 'not in my dictionary' is a variant of the more common 'don't/doesn't know the meaning of the word'.

Me, worry? I don't know the meaning of the word.

He didn't know the meaning of the word 'failure'.

b