A Cannabis Connoisseur is an individual with a vast knowledge in anything related with Cannabis. This individual can tell you everything there is to know about cannabis. From the name of the strain to the flavor and the type of highs. He can identify Indicas from Sativas, and anything in between. He can also give you a list of recipes that include cannabis.
Mundo: "So what kind of bud do you have today man?"
Larry: "Oh, I got some New York City Sour Diesel. Man, this one is bomb. Just look at the soft green color on this, and all the tri-combs. It has a strong scent, smells kind of dank. The texture is just perfect, it's soft, spongy, and it's soo sticky. The high on this strain is killer! Compared to that Afghani Kush, this one kills it."
Mundo: "Damn, you're a total cannabis connoisseur."
For another more visual example watch the film "Pinneaple Express". The scene where Seth Rogen goes to buy weed and James Franco describes the different types and tries to go in deepth with all the details. James comes off as a total Cannabis Connoisseur.