1. In a harmfully insidious manner
   - insidiously 
2. In a noxiously baneful way
   - banefully

See also: pernicious

• factor V
• factor VII
• factor VIII
• factor X
• factor XI
• factor XII
• factor XIII
• factorage
• factorial
• factoring
• factorisation
• factorise
• factorization
• factorize
• factory
• factory farm
• factory price
• factory ship
• factory whistle
• factory worker
• factory-made
• factotum
• facts of life
• factual
• factuality