What is "sybilline"

Usage examples of "sybilline".

The dramatic page which she devoted to this sybilline phrase must be read to gauge the full imagination of the psychoanalyst, who had no qualms about basing the whole of her Oedipean edifice on feet of clay: a note at the foot of a page, freely interpreted and promoted to the rank of a crucial event.

This way Violet had of seizing first not the most obvious sense of what people said to her but some other, interior echo or reverse side of it was a thing that baffled and frustrated her husband, who sought in her sybilline responses to ordinary questions some truth he was sure Violet knew but couldn't quite enunciate.