Can you help me find a word?

Reticent?

Cautious or guarded.

@Hawaii_Jake Discretion or discreet?

I would also go with “discreet”.

Circumspect

Discretion is closest. I don’t know why I have it stuck in my head that it starts with a “c”.

I (cough, cough) like @ucme ‘s answer.

Haha @janbb that’s because it is clearly the absolute correct answer & as such, you are forgiven ;-}

Well, I concur, @ucme is correct. It fits the definition, the example, and starts with the letter ‘C’ Several answers covered it but didn’t start with ‘C’

Cagey but I like @ucme‘s answer

Considerate?

Circumspect? Considered?

The very word doesn’t have to start with the letter C and could just have that letter inside it. Or there was no letter C at all.

This happens to me too when trying to recall a person’s name. I would associate it with a letter only to find out later there was no such letter in the name.

Could the word the OP was asking be “tact”? Discreet would be my first guess too. Also how about “comport”? Conscientious?

Tact.

It doesn’t start with a “c”, but “prudent” is the first word that popped into my head. BTW, it’s a Cardinal virtue