harmful, elusive, damaging, unsafe, pestilent, deadly, hazardous, subtle, injurious, perilous, risky, ruinous, dangerous, seductive, pernicious, baneful, disastrous.
Mrs. Hudson looked at first as if this could be but an insidious
device for increasing her distress by the assistance of irony.
" But ever prowls th' insidious
foe, And listens round the fold" This was too much.
He asked De Vayne to a dessert, and took care that the wines should be of an insidious