There are a lot of words that have been used to describe Elon Musk. Ambitious. Bold. Awkward. Optimistic. But cautious?

That's the newest trait being pegged to the Tesla and SpaceX CEO after an analysis by IBM's Watson supercomputer. Watson's Personality Insights software analyzes written and spoken communication to produce scores for certain personality traits. It gave Musk a cautious score of 0.96 out of a possible 1.00--the highest of any tech CEO it studied.

The goal of Personality Insights is to "help businesses understand their customers at a deeper level," according to the product's About Me page. "It can help businesses learn their clients' preferences, improve customer satisfaction, and strengthen client relations."

In a recent study first spotted by CNBC, career advisement startup Paysa decided to use the program to analyze some of the tech world's top executives. The company gathered a minimum of 2,500 words spoken by each leader--from books, essays, transcripts from speeches and interviews--and fed them to Watson.

The results are pretty surprising. Musk's ventures--self-driving cars, rocket launches, alternative forms of energy--don't seem all that cautious on the surface. Nor do his bold goals (civilization on Mars, anyone?) or his often overly ambitious timelines for doing so.

But Paysa points out that it's possible to be adventurous in seeking new opportunities for success without taking risks that could potentially be costly. Even so, merging Tesla with the unprofitable SolarCity last year at a cost of $2.6 billion probably doesn't qualify as cautious either--and Musk was widely panned by financial analysts for his decision to do so. Musk does have a fairly straightforward, nonflashy, halting manner of speaking (some might call it awkward), so it's possible that played into the results.

According to its website, IBM created the Personality Insights software using recent studies that connect vocabulary to certain personality traits. It trains the system's machine learning algorithm by feeding it text from people's Twitter feeds along with scores from their personality surveys.

Paysa also analyzed which tech leaders were most assertive, with Microsoft CEO Satya Nadella leading, followed by Bill Gates and Mark Zuckerberg. Tim Cook, Jeff Bezos, and Oracle co-founder Larry Ellison were found to be the most imaginative. HP CEO Meg Whitman was the top finisher for achievement-seeking, and Zuckerberg was found to be the most uncompromising.

Cisco CEO Chuck Robbins finished just behind Musk in the cautious category, followed by Nadella and Ellison.