Origin: French suffix -eur
Connoisseur has 2 different meanings across 1 category:
an expert able to appreciate a field; especially in the fine arts
A specialist in a given field whose opinion is highly valued, especially in one of the fine arts or in matters of taste
The word "connoisseur" comes from the French connoître, which originally meant "to know." It entered English usage between 1705 and 1715.