insidious

What does “insidious” mean?

adjective.proceeding in a gradual, subtle way, but with harmful effects.

SAT Usage

insidious is often used in contexts related to subtle dangers, such as health issues, social dynamics, or deceptive behaviors. It emphasizes the harmful effects that may not be immediately obvious, distinguishing it from words like "overt," which suggests clear and direct actions.

Common Confusions

Insidious implies a subtle and gradual danger that is harmful, while blatant usually suggests an obvious and conspicuous presence that cannot be ignored.

Example Sentences

• The disease spread in an insidious way, with symptoms appearing only after severe damage.

• The battle was lost due to the actions of insidious defectors.

• The insidious consequences were difficult to predict.

Word Parts: How to Remember “insidious”

Break “insidious” into its parts: in- (into). Knowing roots like these helps you decode unfamiliar SAT vocabulary.

• Prefix: in- into (Latin)