The term metaphysics has multiple meanings
in philosophy, the two primary ones being:
That part of traditional philosophy which is concerned with the fundamental nature of reality and "existence".
Philosophical views which are non-dialectical, or in other words, views which do not approach things in a dialectical way. (This is the most common sense of the term within Marxist philosophy.)
In any of its senses, metaphysics has a very bad reputation for being obscure, confused, or even gibberish. This has led to much appropriate hostility to metaphysics, as evidenced in the following extract from Lord Byron: