What is the opposite of regal?

The opposite of regal depends on what aspect of the word you want to contrast:

If you're thinking of royalty and grandeur:

* Common

* Humble

* Unpretentious

* Modest

* Plain

* Down-to-earth

If you're thinking of dignity and poise:

* Unrefined

* Boorish

* Crude

* Vulgar

* Uncouth

* Disrespectful

If you're thinking of authority and power:

* Submissive

* Weak

* Powerless

* Subordinate

* Unimportant

The best opposite for "regal" will depend on the specific context in which it's used.