sad ‧ do /ˈsædəʊ $ -oʊ/ BrE AmE noun ( plural saddos ) [countable] informal
[ Word Family: noun : ↑ sadness , ↑ saddo ; adjective : ↑ sad , ↑ saddening ; verb : ↑ sadden ; adverb : ↑ sadly ]
someone who you do not respect, especially because you think their interests are boring or strange:
a bunch of saddos dressed up as science fiction characters