A vowel combination consisting of a weak vowel and a strong one.
It is more commonly used as an insult, seeing as it is a legitimately funny word.
There is a diphthong in "loud."
YOU'RE A DIPHTHONG.
A small article of clothing worn by a homosexual man under a swimsuit or alone. Especially used at nighttime.
When I went swimming with Peter, he was wearing the sexiest diphthong.