Definition of "protean"

Virus infection of the blood and bone marrow is probably responsible for all forms of the disease. The viral theory of origin accounts for the protean manifestations of the condition.

1954 February 15, Henry E. Michelson, “The Syndrome of Lupus Erythematosus”, in Modern Medicine, volume 22, number 4, Minneapolis, Minn.: Modern Medicine Publications, Inc., page 96

[…] the word's protean expressiveness has been observed in a xeroxlore item printed in Robert Anton Wilson's Playboy's Book of Forbidden Words […]

1980, Gershon Legman, The New Limerick

He loved to show off his protean talent.

1987, William A. Henry III, Time Magazine, volume 129

In the intervening decades she has become a protean figure, an emblem of different things to different people, depending upon their viewpoint — a visionary, a victim, a martyr, a feminist icon, a schizophrenic, a virago, a prisoner of gender — or, perhaps, a genius, as both Plath and Hughes maintained during her lifetime.

2020 October 27, Daphne Merkin, “Shifting the Focus From Sylvia Plath’s Tragic Death to Her Brilliant Life”, in The New York Times‎