"독서하다는 책을 읽다라는 뜻이고 읽다는 목적어가 없어서 무엇이든 읽을 수 있음" It looks like you took some of the words the wrong way: 1. There is no reference to "or" in the sentence that your "독서하다 or 책을 읽다라 ..." suggests. 2. The original sentence mentions 목적어, which is not "purpose" but "object (of a verb)". 3. There is no reference to "read both" or "use both", but only "any reading" (indeterminate). In short, it is saying "독서하다" does not take an object (it is intransitive) so can be used in any context of "reading". Generally, 독서하다 is never used with a specific book as an object, where as 읽다 usually is. So the sentence is pointing out this attribute of 독서하다 which makes it distinct from 읽다. But the sentence is a little unclear as written, which probably confounds your problem of understanding it. As written, it is like: 독서하다 means "to read" and since "read" doesn't have an object, it can read anything. (problem is in 독서하다 becoming the subject of "can read") To make it clearer, it can be written like: 독서하다 (also) means "to read", but since "read" here doesn't have an object, it can refer to any act of reading. => "독서하다"는[도] "책을 읽다"라는 뜻이지만 여기서는 읽는 것의 목적어가 없어서 모든 책 읽는 행위를 의미할 수 있음.

독서하다 = 책을 읽다. 100% the same. As you may know, Korean uses a lot of Chiness characters and their meaning (not the pronunciation) 독서 = 독+서 = 읽다 + 책 Do you understand?