I’m back with a new FG. It’s very easy to understand. I will post one new puzzle every day and anyone can answer it (in thread). If a person gets the correct answer before I post the next puzzle, they win a point. If no-one gets the answer by the time the next puzzle is posted, I will reveal it. It really is that simple. Good luck :D
I think ball fits the rule. It can be yellow, and has only one vowel which is an A. (catamaran, banana, macaw).
Otherwise balaclava (polysyllabic, usually black, but could be yellow).