Strange
Part of speech: adjective
Definition: Not normal; odd, unusual, surprising, out of the ordinary. Unfamiliar, not yet part of one's experience. Having the quantum mechanical property of strangeness.
Example sentence: I have learned silence from the talkative, toleration from the intolerant, and kindness from the unkind; yet, strange, I am ungrateful to those teachers.
Unknown
Part of speech: adjective
Definition: Not known; unidentified; not well known.
Part of speech: noun
Definition: A variable (usually x, y or z) whose value is to be found.Any fact or place about which nothing is known (as in the phrase "into the unknown").