Synonyms of the word

unseen

• adj. Not seen or discovered.
• adj. Unskilled; inexperienced.
• v. past participle of unsee.
• n. An examination involving material not previously seen or studied.

belief

• n. Mental acceptance of a claim as true.
• n. Faith or trust in the reality of something; often based upon one's own reasoning, trust in a claim, desire…
• n. (countable) Something believed.
• n. (uncountable) The quality or state of believing.
• n. (uncountable) Religious faith.
• n. (in the plural) One's religious or moral convictions.

invisible

• adj. Unable to be seen; out of sight; not visible.
• adj. Not appearing on the surface.
• adj. (Internet) Apparently, but not actually, offline.
• adj. (psychology) That is ignored by a person.
• v. To invisiblize.
• n. (obsolete) An invisible person or thing; specifically, God, the Supreme Being.
• n. (obsolete) A Rosicrucian; so called because avoiding declaration of his craft.
• n. (obsolete) One of those (as in the 16th century) who denied the visibility of the church.

undetected

• adj. not found; undiscovered.

unobserved

• adj. not seen or observed.
• adv. whilst not being seen or observed.

unseeable

• adj. invisible.
• adj. unimaginable.