They're wonderful. They're obscure. They're often quite pointless.
Lookups spiked on October 8, 2014.
The first person to be diagnosed with Ebola in the United States, Thomas Eric Duncan, died of the disease in Texas. A hospital spokesperson said, "Mr. Duncan succumbed to an insidious disease, Ebola."
When used to describe a disease, insidious means "developing so gradually as to be well established before becoming apparent." In more general contexts, it means "having a gradual and cumulative effect" or "subtle."
It comes from the Latin word meaning "cunning" or "deceitful" and is related the Latin word for "ambush."
Photo credit: wikimedia.org
See Definitions and Examples »
Get Word of the Day daily email!