Categories of vegetarians:

 Vegan -- avoids using all animal products, including leather, wool, honey...
 Strict Vegetarian -- avoids eating all animal products that require killing an animal, and may or may not avoid animal-based food products that don't require killing an animal.
 Ovo-lacto vegetarian -- Eats animal-based food products that don't require killing an animal, such as milk and eggs; may or may not wear leather/wool
 Cheesy ovo-lacto vegetarian -- Eats animal-based food products that don't require killing an animal, such as milk and eggs, but does not enquire if cheese was made without rennet, because it's cheese.
 Ovo-lacto-pescatarian (aka vegaquarian) -- eats eggs, dairy products and fish.
 Fruitarian -- eats fruit and only fruit
 Flexitarian -- eats meat occasionally. Is generally fine with chicken stock, rennet, gelatine, lard...
 Wishy-Washy Flexitarian -- doesn't try to practise vegetarianism where it would surely result in some sort of conflict
 Pragmatarian -- vegetarian takes a don't ask, don't tell policy towards rennet, chicken stock, gelatine, lard...
 Squickatarian -- vegetarian who won't eat mock-meat products.
 Parentarian -- vegetarian except while visiting relatives (who never really got the hang of young Robin not eating meat, and it's only got a little bit of bacon and chicken stock, really)
 Antiparentarian -- only veg/kosher/vegan when the parents are around
 Ethicarian -- eats anything sustainably farmed.
 Baconian -- bacon is a vegetable.
 Antibaconian -- Eats anything except pigmeat.
 Freegan -- eat anything as long as it's free. Dumpster diving, etc.
 Visitarian -- won't eat anything that looks like its source animal (chicken on the bone, fish with the head attached, whole roast suckling pig)
 Hunterian -- vegetarian unless they had killed the animal themselves
 Theoretical Hunterian -- vegetarian unless they think they'd be able to kill the animal themselves
 Proper Foodian -- won't eat anything that doesn't look and taste like something they'd have eaten at home when they lived with their parents
 None of the above