insidiously

/ɪnˈsɪdiəsli/
adverb
  1. In a gradual, subtle way that causes harm.
    • The rumor spread insidiously through the small town before anyone could stop it.
    • The invasive plant grew insidiously, choking out native species.
    • Stress can insidiously damage your health over many years.
  2. In a treacherous or deceitful manner.
    • She insidiously manipulated her coworkers to take credit for their work.
    • The hacker insidiously installed malware that stole passwords one by one.
    • The advertisement insidiously suggested that buying the product would solve all problems.
What does "insidiously" mean? | whatsthatwordmean | whatsthatwordmean