Synonyms of the word

stranger

• adj. comparative form of strange: more strange.
• n. A person whom one does not know; a person who is neither a friend nor an acquaintance.
• n. An outsider or foreigner.
• n. A newcomer.
• n. (humorous) One who has not been seen for a long time.
• n. (obsolete) One not belonging to the family or household; a guest; a visitor.
• n. (law) One not privy or party to an act, contract, or title; a mere intruder or intermeddler; one who interferes…
• v. (obsolete, transitive) To estrange; to alienate.

alien

• n. A person, animal, plant, or other thing which is from outside the family, group, organization, or territory…
• n. A foreigner residing in a country.
• n. Any life form of extraterrestrial origin.
• n. One excluded from certain privileges; one alienated or estranged.
• adj. Pertaining to an alien.
• adj. Not belonging to the same country, land, or government, or to the citizens or subjects thereof; foreign.
• adj. Very unfamiliar, strange, or removed.
• v. (transitive) To estrange; to alienate.
• v. (law) To transfer the ownership of something.

interloper

• n. (obsolete) An unlicensed or illegitimate trader.
• n. One who interferes, intrudes or gets involved where not welcome, particularly a self-interested intruder.

intruder

• n. Someone who intrudes.

trespasser

• n. One who trespasses; an interloper.

unknown

• adj. (sometimes postpositive) Not known; unidentified; not well known.
• n. (algebra) A variable (usually x, y or z) whose value is to be found.
• n. Any fact or place about which nothing is known (as in the phrase "into the unknown").
• n. A person of no identity; a nonentity.