A sniffle is a slight cold. You can also say that someone has the sniffles. to keep sniffing in order to stop liquid from running out of your nose, especially when you are crying or you have a cold (sniff). have the sniffles if you have the sniffles, you keep sniffing, especially because you have a cold
inhale audibly through the nose; "the sick student was sniffling in the back row"