Short answer
There is no perfect one-word substitute, because “mysticism” has more than one meaning. The closest common alternatives are spirituality, contemplation, transcendentalism and mystical experience, and which one fits depends on how you are using the word.
Synonyms by meaning
Mysticism as direct experience of the divine or ultimate reality
- Mystical experience
- Contemplation
- Spiritual union or communion
- Illumination or enlightenment (in some religious contexts)
- Gnosis, a Greek term for direct, inner knowledge, used in Gnostic and esoteric writing
Mysticism as a general spiritual outlook
- Spirituality
- Transcendentalism, though this also names a specific nineteenth-century American movement
- Metaphysics, in the loose popular sense, though in philosophy it means something else
Mysticism as mystery or hidden meaning
- Mystique
- Arcana, meaning secrets or hidden things
- The numinous, a term for the sense of the sacred
Related adjectives include mystical, mystic, transcendent and visionary. A person who practises mysticism is a mystic, which is the standard word.
Near-synonyms that mean something different
Some words are often used for mysticism but are not equivalent.
- Occultism concerns practices aimed at working with hidden forces, such as magic and divination. Mystics may have no interest in those. The overlap and differences are covered in the occult explained.
- Esotericism describes teachings meant for initiates, which may or may not be mystical; see esotericism vs occultism vs mysticism.
- Mysticism in a critical sense is sometimes used to mean vague or irrational thinking. In that use, synonyms might be “obscurantism” or “woolly thinking,” but these are negative judgments, not neutral equivalents.
- Mysterious means hard to explain and does not imply any spiritual content.
The full meaning of mystical
As an adjective, “mystical” usually means relating to the direct experience of God or ultimate reality, or having a spiritual meaning beyond ordinary understanding. It can also mean something spiritually symbolic, as in “a mystical interpretation of a text.” In casual speech it often just means mysterious or awe-inspiring. Context decides.
Mystical and spiritual art
“Spiritual art” is a loose category: artwork that expresses or supports religious or spiritual themes. Examples include icons, mandalas, devotional paintings and sacred architecture. “Mystical art” tends to stress visions, symbolism or inner experience. The terms are not fixed, and no definitive list of categories exists. The question of what counts as “the seven types of art” depends on the system used. The most familiar older list is painting, sculpture, architecture, music, poetry, dance and cinema, though other lists exist. For one example of symbolic design, see sacred geometry.
Choosing the right word
- Writing about a religious experience: use mystical experience, contemplation or communion.
- Writing about a general outlook: use spirituality (the difference is explained in mysticism vs spirituality).
- Writing about secret or inner teachings: use esotericism.
- Writing about magic and divination: use occultism.
If you are unsure, “mysticism” itself is usually the clearest choice. You can also read about common spiritual practices for examples of what these terms refer to in daily life.