The CEO of $500 million startup Rent the Runway thinks this is the biggest fashion mistake women make at work

Jennifer Hyman knows a thing or two about fashion.

In 2009, she and her Harvard Business School classmate Jennifer Fleiss started Rent the Runway, a luxury clothing and accessories rental company. The business was last valued at about $500 million by venture capitalists and it has raised more than $110 million to date.

Hyman, who recently attended Marie Claire's Power Trip summit, a women's networking event sponsored by Dell, Intel, JetBlue, Shiseido, Tacori, and W Hotels, says there's one major fashion mistake she thinks many women make at work: "Too much black and navy and neutral boringness."

"You should live a little!" she tells Business Insider. "Many people are afraid to wear something that feels authentic to them for fear of not being 'office appropriate.' But the workplace is a new world and we have the power as women to change it and to be our real authentic selves every day."

However, it's important to note that in some companies, jobs, or industries, workers are encouraged to stick to boring black suits - and dressing "authentically" isn't always an option. But there are easy ways to spruce up any dull work wardrobe. For instance, you can add a colorful scarf or a fun jeweled necklace to your monochrome outfit.

"What we wear is a great way to show off our diverse personalities," Hyman concludes.

But before you make any drastic wardrobe changes, find out what's appropriate according to your company's dress code.