Many remain unclassified simply for lack of data, but among the better-investigated ones that continue to resist easy classification are:

The wide variety of the labels and their varying use mean that they defy easy philatelic classification.

Yet Amanda found there was something primitive about him, and he seemed to defy easy classification.

His work eschews easy classification, moving freely between jazz, theatrical and concert worlds.

They defied easy classification and would not fit into any of the pigeonholes I had constructed.

Kathleen had gotten under my skin the second I saw her, and she defied easy classification.

Lawrence Cremin's historical approach is commonly considered liberal, although it defies easy classification.

The ballet is so rich in ideas that it defies easy classification.

Although usually grouped with country music singers, Miller's unique style defies easy classification.

As in much of his career, these defy easy classification.