Common Prefixes:
* Hot- (hot dog)
* Watch- (watchdog)
* War- (war dog)
* Guide- (guide dog)
* Street- (street dog)
* Service- (service dog)
* Blood- (bloodhound)
* Sea- (seadog)
* Fire- (fire dog)
* Sheep- (sheepdog)
* Toy- (toy dog)
Less Common Prefixes:
* Spaniel- (spaniel dog)
* Husky- (husky dog)
* Poodle- (poodle dog)
* Bull- (bulldog)
* Fox- (foxhound)
* Pointer- (pointer dog)
* Retriever- (retriever dog)
Humorous Prefixes:
* Super- (superdog)
* Mega- (megadog)
* Astro- (astrodog)
* Cyber- (cyberdog)
* Disco- (discodog)
You can also add prefixes that are relevant to the context you're using the word in. For example, if you're talking about a dog that is particularly friendly, you could use "friendly-dog."
Have fun playing around with prefixes and creating your own unique "dog" words!