When:
Lookups spiked on April 10, 2012.
Why:
The word was often invoked on the 100th anniversary of the Titanic's departure from Southampton, England. For example, as The Guardian observed:
"Part of the enduring pull of the Titanic story is that it, yes, illustrates man's hubris to the point that the ship itself has become a cliched metaphor."
Hubris means "exaggerated pride or self-confidence" and comes directly from the Greek word with the same meaning.
Hubris is nearly always used in this context to refer to human ambitions - and not, for example, to the specific actions of the Titanic's crew.
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Merriam-Webster unabridged