Hi lucky12341,
You can protect a cell without protecting the sheet using data validation. However, this is just a protection against inadvertent editing, but not against deliberate or malicious editing because the validation can be undone by the user.
If you want to validate a cell against editing simply validate to allow only text strings with fewer than 1 characters to be entered. You can also use validation to give the user a message when the user selects a cell within the validated range, like "this cell is locked against inadvertent editing".
Damon