From the Merriam-Webster Online Dictionary:
Etymology: Middle English gibet, from Anglo-French
Date: 13th century
1 : gallows 1a 2 : an upright post with a projecting arm for hanging the bodies of executed criminals as a warning.
Comment: Do we really need to use a 13th century word in a 21st century world?
Etymology: Middle English, from Latin ineffabilis, from in- + effabilis capable of being expressed, from effari to speak out, from ex- + fari to speak — etc.
Date: 14th century
1 a: incapable of being expressed in words : indescribable
Comment: Believe it or not, with all the reading that I have done over many years, I doubt if I have seen this word more than 3 or 4 times and it apparently was never important to the meaning of the sentence because I never knew what it meant until now.
We'll be seeing more of ineffable since it was voted to be used. I don't know about gibbet though.