To many the word "occult" invokes thoughts of "devil worship" or other dark practices.
In reality however occult does not mean anything sinister whatsoever, it rather literally means "hidden" or "secret" e.g. as in "hidden knowledge" or knowledge beyond the scope of most people. Related word is "esoteric" which literally means "only understood by a privileged few" or only available to a small number of enlightened, awakened or initiated people.
Study of the occult is known as "occultism" and is practiced by an "occultist" and can include such diverse subjects as magic, astral projection and out of body experiences, esp, astrology and many similar practices. The occultist is usually studying knowledge or wisdom that is considered to be just or far below common knowledge, i.e. the knowledge of the general population, although the full scope is usually limited to mystical, esoteric or paranormal areas.
There are practices that historically have given occultism a bad name, and example being "voodoo" as practiced in Haiti where "voodoo dolls" are regarded with terror, mostly due to a misunderstanding of what voodoo is all about.
Unfortunately, as a result, the general public tend to look upon the occult or occultism as something evil, like witchcraft for example, perceptions often a result of indoctrination by the church who tends to associate all of these practices with the "work of the devil". Indeed. it was due to this ignorance at the time the "burning times" took place, where witches, and probably anyone and everyone else arbitrarily deemed to be loosely involved with the occult where hunted down, subjected to some arbitrary tests that the victim could not possibly win, and then executed in a horrible and often drawn out way, usually by "burning at the stake".
Of course as with many things of this nature, there are people who abuse Universal powers for their own ends, such as "black magicians" for example, and thus give these practices a bad name, or even an object of fear; something to be avoided at all costs.
Fortunately these days both the church and people generally are more enlightened, tolerant at least, and tend to mostly ignore anything considered to be "of the devil" and sometimes even pray for them.
In religious terms; religious people usually consider the occult to be anything not achieved by or through God.
Other examples of what are generally regarded as occult practices are: alchemy, channelling, divination, fraternal orders, mysticism, psychic powers, heretics, and even angels.
Esoteric knowledge is studied and practiced by an esotericist being the practice of esotericism, the word being derived from the Greek word "esoterikos", and is considered to be information that cannot be generally obtained during the normal course of things, but rather requires an additional or deeper level of knowledge that is often only made available to those who are ready to receive such knowledge.
Esotericism can also be a way of life that involves making a conscious decision to become aware of esoteric events and knowledge, write them down and assimilate them into your Being. A very useful aspect of this practice is meditation where you would write down any information or impressions received during the meditation process.
So in conclusion, I would suggest that if anyone regards the occult, or anything esoteric with fear and trepidation, rather than being fearful or dismissive I would suggest you take the time to read through this and other sites that you might not only see for yourself the sheer scope of these practices, and what they really stand for, but also how they can help you greatly on your own Spiritual journey.