Stud, dust, rust and ruts.
The 4 letter words with the letters q u and d in it include:quadquid
Dumb
Izod
Dour
Dove
Dead
hord
Nonexistant
Hundreds, if not thousands.
Dele
abjectadjectiveadjournadjustdejecteddisjointeddoorjambdrudgejadejudgejaundice
Avid