Bumpkin - I read this word in comic.is this a English word?

Yes. It’s generally used as an insult for someone who is unsophisticated/uneducated, often with the connotation that they had a rural upbringing. It may be a specifically American term; I’ve never heard a British person use it.

Did you look it up in a dictionary?

Yes, "a bumpkin" is an ignorant or unsophisticated person, usually from the countryside.

It's almost always 'country bumpkin', it implies a slow-witted person who does an unspecified agricultural job. It's a real word but you could spend your whole life without needing it.

Yes

It's almost exclusively used in American English in the phrase "country bumpkin". I don't know its origin. It's an insult that means something similar to "hick" or "redneck" to some people. Basically, an unintelligent or simple rural person - like a farmer.

Yes. *Hick* is another similar term. Backwards rural type. Generally used as an insult/stereotype or in a comedy routine. *Redneck* is a more common and current version, slightly different connotation but in the same ballpark.

Others have covered the current meaning, but It's an english word that comes from boom + -kin, with boom being the Dutch word for tree which was borrowed into English here. The word literally means little tree but it isn't used that way in English. Bumpkin is related to the German Bäumchen (little tree).

Yep. It's an old-fashioned, informal, fairly derogatory (but not really offensive) term that means something like "uneducated country person".

Bumpkin: An adjective, describing an uneducated, stupid rural person. Blumpkin: A verb, describing the act of oral sex, with the receiver being on the toilet.

A country bumpkin is usually used when someone who was raised outside of a city and is...simple. Redneck being a class-specific insult, bumpkin is the equivalent of calling someone stupid/simple because they're not from a city. Also some classism, but more "because you're from the country, you don't understand how \[something commonly used in cities\] works".