Describes a person who reads a lot and loves reading. Neutral, slightly positive connotation.
She is a great bookworm and reads three books a week.
祖父は読書家で、書斎には何千冊もの本がある。
My grandfather is an avid reader, and there are thousands of books in his study.
He's a huge bookworm and reads for hours every day.
She is known as an avid reader.
He's famous for being a bookworm.
読書 means the act of reading itself, while 読書家 refers to a person who reads a lot; learners sometimes confuse the noun for the activity with the noun for the person.
Used when counting people in formal or service contexts; for a person in general, 人 is the ordinary counter, but it is not in the requested inventory for this noun.
Compound of 読書 (reading books) and 家 (person with a certain trait or profession).