In 2016, former Secretary of State Hillary Clinton was deemed "electable" by analysts just four years after former Massachusetts Gov. Mitt Romney carried the same label in the race against President Barack Obama, a contest that Romney lost. This election, pundits have dubbed former Vice President Joe Biden as the most "electable" Democrat among a field of more than 20 candidates, in large part because early polls, including the USC Dornsife/Los Angeles Times poll, indicate he is the favorite so far.
source https://www.lifetechnology.com/blogs/life-technology-news-blog/for-the-presidential-race-electability-could-decide-who-wins-and-who-loses