Describes a person who reads a lot and loves reading. Neutral, slightly positive connotation.
彼女は大変な読書家で、週に三冊は本を読む。
She is a great bookworm and reads three books a week.
祖父は読書家で、書斎に
He's a huge bookworm and reads for hours every day.
My grandfather is an avid reader, and there are thousands of books in his study.
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).