insidious
adjective
[ ɪnˈsɪdɪəs ]
• proceeding in a gradual, subtle way, but with very harmful effects.
• "sexual harassment is a serious and insidious problem"
Similar:
stealthy,
subtle,
surreptitious,
sneaking,
cunning,
crafty,
Machiavellian,
artful,
guileful,
sly,
wily,
tricky,
slick,
deceitful,
deceptive,
dishonest,
underhand,
backhanded,
indirect,
sneaky,
Origin:
mid 16th century: from Latin insidiosus ‘cunning’, from insidiae ‘an ambush or trick’, from insidere ‘lie in wait for’, from in- ‘on’ + sedere ‘sit’.
