Insidious
hardNegative tonein-SID-ee-us
adjective
Definition
Proceeding in a gradual, subtle way with harmful effects
Memory hook
IN-SIDIOUS: danger lurking INSIDE, hidden — proceeding harmfully but in a subtle, stealthy way.
Word roots
Learning roots unlocks whole word families. Study common GRE root words.
Examples
“The insidious spread of misinformation undermined public trust.”
“Cancer is an insidious disease that often goes undetected.”
Test yourself
Fill in the blank with the right word:
“The ______ spread of misinformation undermined public trust.”
Show answer
insidious
Synonyms
Antonyms
Categories
GRE Tip
Insidious is a hard-difficulty GRE word. On the GRE, you might see it paired with synonyms like "treacherous" or "stealthy" in Sentence Equivalence questions. Look for contrast clues (however, despite, although) that signal the opposite meaning. Words like "overt".
Related GRE Words
furtive
Attempting to avoid notice or attention, typically because of guilt or a belief that discovery would lead to trouble
perfidious
deceitful and treacherous; disloyal
surreptitious
Kept secret, especially because it would not be approved of
baneful
Causing harm or ruin; pernicious; destructive
deleterious
Causing harm or damage; injurious
pernicious
Having a harmful effect, especially in a gradual or subtle way
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