Parole

This question is very easy if dissected, but the use of the phrase 'word of honour' confused at least one contestant that I know of – preventing them from fully dissecting it.

dictionary.com explains that 'parole' is an abbreviation for the French term parole d'honneur. Wikipedia defines the French word parole (on its own) to mean "speech [or] spoken words" but also (by implication), "promise".

dictionary.com also gives 'parol' as an English word (pronounced the same as 'parole'), meaning "something stated or declared". 'By parol' means "by word of mouth, [or] orally."

So to say that 'parole' on its own means 'word of honour' could, IMHO, be described as quite misleading.