A hog in armour is still but a hog.

External finery, status, or protection does not necessarily alter a person's basic character. The image dismisses appearances that try to make someone seem more dignified, capable, or worthy than their conduct suggests.

It can also warn that power or impressive trappings may leave underlying faults untouched. As a blunt, contemptuous judgment that labels someone a “hog,” it can demean and oversimplify a person or situation rather than offer neutral advice about self-improvement.

Use it to challenge inflated presentation or authority when someone's conduct still seems crude, foolish, or unworthy. Because the comparison is insulting and directly labels a person a “hog,” it suits sharp rebuke or satire but may be needlessly offensive in personal conversation.