For "stark" meaning "completely bare or plain":
* Ornate
* Elaborate
* Decorated
* Adorned
* Rich
* Luxurious
For "stark" meaning "harsh or severe":
* Gentle
* Mild
* Subtle
* Nuanced
* Compassionate
* Forgiving
For "stark" meaning "bright and clear":
* Dim
* Faint
* Hazy
* Vague
* Indistinct
For "stark" meaning "completely and utterly":
* Slight
* Partial
* Limited
* Minor
It's important to consider the specific sentence and the intended meaning to choose the most appropriate antonym.