What Does DUM Mean? (Using DUM Online)DUM means "Stupid".
Definition for DUMDUM means "Stupid". This is the most common definition for DUM on Snapchat, WhatsApp, Facebook, and Twitter. Here is some more information about DUM:
2: Quite easy to guess
Adults and Teenagers
Using DUM on a Cell Phone (SMS Texts, Whatsapp, and Yubl)