1. Beguiling but harmful
   "insidious pleasures" 
2. Intended to entrap 
3. Working or spreading in a hidden and usually injurious way
   "glaucoma is an insidious disease"
   - pernicious, subtle

See also: dangerous, harmful, insidiously, insidiousness, seductive, unsafe

• take notice
• take office
• take on
• take one's lumps
• take orders
• take pains
• take part
• take place
• take pride
• take root
• take shape
• take sides
• take stage
• take stock
• take ten
• take the air
• take the bull by the horns
• take the cake
• take the count
• take the field
• take the Fifth
• take the Fifth Amendment
• take the floor
• take the Mickey
• take the piss