Used mainly in casual conversation among friends or on social media. Not for formal situations. After he tripped over his own feet, everyone called him a doofus.
Pro Tip 2/3
Mild Insult
It's a playful insult for small mistakes or silly behavior, not for serious criticism. She wore her shirt inside out like a total doofus today.
Pro Tip 3/3
Not Global
It’s understood in English-speaking countries but may not be known in other cultures. My British cousin called his friend a doofus, and we all laughed.