fatuous, fastuous

Fatuous or fatuous describes words that are foolish, airy or thoughtless --
He counts himself a scholar, but his arguments are usually fatuous.
If she opens her mouth and makes one more fatuous remark, I'll weep.

Fastuous or fastuous means arrogant or ostentatious --
She had a regal bearing, and greeted people with a fastuous nod.
She was always overdressed, fastuous if not fashionable.

Now that you know that, you can say --
"The wedding dinner was unstylishly fastuous; he felt a need to excuse it with fatuous explanations."