Special pleading
Etymology
The phrase began as a legal term for pleading special circumstances that take a case outside the ordinary rule. In everyday argument it curdled into a criticism: inventing an exception with no principled basis. The tell is a carve-out that exists only to protect the arguer’s position.
noun phrase · /SPESH-ul PLEE-ding/
Applying a rule or standard to others while claiming an unjustified exemption for your own case.
What it names
Spotting it exposes the double standard behind "the rules are different for me" when no real difference is shown.
Example
He insists everyone must show their work, then refuses to explain his own figures because he’s "experienced" — special pleading.
Related idea
The no true Scotsman is a close relative, but it edits definitions rather than granting itself an exemption.