Meanings of thin veneering in English

Walpole's romanticism was a thin veneering; underneath it, he was a man of the eighteenth century.

His deep, simple, German nature revolted from Parisian frivolity, in which he found only sensuality and coarseness, disguised under a thin veneering of social grace.

"A mere trifle; it is only a thin veneering just to give a secure and comfortable foothold," remarked the professor.