Common words:
* soup
* group
* would
* could
* should
* youth
* through
* fruit
* proof
* wound
Less common words:
* bough (branch of a tree)
* cough
* enough
* rough
* tough
Proper nouns:
* Gloucester (a city in England)
* Toulouse (a city in France)
Note: The spelling "ou" can also make other sounds, like the "ow" sound in "house" or the "oo" sound in "food".